MDA2AV · MDA2AV · Jun 6, 2026 · Jun 6, 2026 · Jun 6, 2026
@@ -121,12 +121,13 @@ components_manager:
         hello-world-db:
             dbconnection#env: DATABASE_URL                      # HttpArena benchmark env
             dbconnection#fallback: postgresql://bench:bench@localhost:5432/benchmark?sslmode=disable  # local dev
-            min_pool_size: 64
+            min_pool_size#env: DATABASE_MAX_CONN                # pre-warm all connections at startup
+            min_pool_size#fallback: 256                          # local dev
             max_pool_size#env: DATABASE_MAX_CONN                # HttpArena benchmark env (set to 256)
             max_pool_size#fallback: 256                          # local dev
             # min == max: pre-warm all connections at startup for benchmark
             blocking_task_processor: fs-task-processor
-            max_queue_size: 512
-            connecting_limit: 15
+            max_queue_size: 4096
+            connecting_limit: 256
             ignore_unused_query_params: true
             connlimit_mode: manual
@@ -10,15 +10,14 @@
 #include <userver/http/common_headers.hpp>
 #include <userver/storages/postgres/cluster.hpp>
 #include <userver/storages/postgres/component.hpp>
-#include <userver/storages/postgres/io/json_types.hpp>
 #include <userver/storages/postgres/result_set.hpp>
 
 namespace userver_httparena::async_db {
 namespace {
 struct ItemRow {
   int64_t id;
-  std::string name;
-  std::string category;
+  std::string_view name;
+  std::string_view category;
   int64_t price;
   int64_t quantity;
   bool active;
@@ -48,24 +47,23 @@ std::string Handler::HandleRequestThrow(const userver::server::http::HttpRequest
 
   // Matches
   // https://www.http-arena.com/docs/test-profiles/h1/isolated/async-database/implementation/
-  // kSlave falls back to master if no read replica is available
-  auto res = pg_->Execute(userver::storages::postgres::ClusterHostType::kSlave,
+  auto res = pg_->Execute(userver::storages::postgres::ClusterHostType::kSlaveOrMaster,
                           "SELECT id, name, category, price, quantity, active, tags, "
                           "rating_score, rating_count FROM items "
                           "WHERE price BETWEEN $1 AND $2 LIMIT $3",
                           min, max, limit);
 
-  const auto rows = res.AsContainer<std::vector<ItemRow> >(userver::storages::postgres::kRowTag);
+  auto items = res.AsSetOf<ItemRow>(userver::storages::postgres::kRowTag);
 
   userver::formats::json::StringBuilder sb;
   {
     userver::formats::json::StringBuilder::ObjectGuard root_guard(sb);
     sb.Key("count");
-    sb.WriteInt64(static_cast<int64_t>(rows.size()));
+    sb.WriteInt64(static_cast<int64_t>(items.Size()));
     sb.Key("items");
     {
       userver::formats::json::StringBuilder::ArrayGuard items_guard(sb);
-      for (const auto& row : rows) {
+      for (const auto& row : items) {
         userver::formats::json::StringBuilder::ObjectGuard item_guard(sb);
         sb.Key("id");
         sb.WriteInt64(row.id);

@@ -1241,6 +1241,32 @@
     "tpl_static": 0,
     "tpl_async_db": 572974
   },
+  {
+    "framework": "userver",
+    "language": "C++",
+    "rps": 137828,
+    "avg_latency": "6.86ms",
+    "p99_latency": "35.00ms",
+    "cpu": "1779.9%",
+    "memory": "373MiB",
+    "connections": 1024,
+    "threads": 64,
+    "duration": "5s",
+    "pipeline": 1,
+    "bandwidth": "411.95MB/s",
+    "input_bw": "7.76MB/s",
+    "reconnects": 413290,
+    "status_2xx": 2067430,
+    "status_3xx": 0,
+    "status_4xx": 0,
+    "status_5xx": 0,
+    "tpl_baseline": 774549,
+    "tpl_json": 776048,
+    "tpl_db": 0,
+    "tpl_upload": 0,
+    "tpl_static": 0,
+    "tpl_async_db": 516832
+  },
   {
     "framework": "uvicorn",
     "language": "Python",

@@ -1241,6 +1241,32 @@
     "tpl_static": 0,
     "tpl_async_db": 210990
   },
+  {
+    "framework": "userver",
+    "language": "C++",
+    "rps": 59270,
+    "avg_latency": "3.79ms",
+    "p99_latency": "29.50ms",
+    "cpu": "403.6%",
+    "memory": "203MiB",
+    "connections": 256,
+    "threads": 64,
+    "duration": "5s",
+    "pipeline": 1,
+    "bandwidth": "177.10MB/s",
+    "input_bw": "3.33MB/s",
+    "reconnects": 177804,
+    "status_2xx": 889058,
+    "status_3xx": 0,
+    "status_4xx": 0,
+    "status_5xx": 0,
+    "tpl_baseline": 333335,
+    "tpl_json": 333509,
+    "tpl_db": 0,
+    "tpl_upload": 0,
+    "tpl_static": 0,
+    "tpl_async_db": 222213
+  },
   {
     "framework": "uvicorn",
     "language": "Python",

@@ -993,6 +993,26 @@
     "status_4xx": 0,
     "status_5xx": 0
   },
+  {
+    "framework": "userver",
+    "language": "C++",
+    "rps": 236485,
+    "avg_latency": "3.75ms",
+    "p99_latency": "11.00ms",
+    "cpu": "5559.7%",
+    "memory": "300MiB",
+    "connections": 1024,
+    "threads": 64,
+    "duration": "5s",
+    "pipeline": 1,
+    "bandwidth": "912.03MB/s",
+    "input_bw": "15.79MB/s",
+    "reconnects": 94584,
+    "status_2xx": 2364854,
+    "status_3xx": 0,
+    "status_4xx": 0,
+    "status_5xx": 0
+  },
   {
     "framework": "uvicorn",
     "language": "Python",

@@ -1428,19 +1428,19 @@
   {
     "framework": "userver",
     "language": "C++",
-    "rps": 978241,
-    "avg_latency": "4.19ms",
-    "p99_latency": "13.40ms",
-    "cpu": "6153.4%",
-    "memory": "445MiB",
+    "rps": 1053894,
+    "avg_latency": "3.89ms",
+    "p99_latency": "9.33ms",
+    "cpu": "6401.3%",
+    "memory": "411MiB",
     "connections": 4096,
     "threads": 64,
     "duration": "5s",
     "pipeline": 1,
-    "bandwidth": "134.31MB/s",
-    "input_bw": "75.57MB/s",
+    "bandwidth": "144.70MB/s",
+    "input_bw": "81.41MB/s",
     "reconnects": 0,
-    "status_2xx": 4891208,
+    "status_2xx": 5269470,
     "status_3xx": 0,
     "status_4xx": 0,
     "status_5xx": 0

@@ -1428,19 +1428,19 @@
   {
     "framework": "userver",
     "language": "C++",
-    "rps": 602547,
-    "avg_latency": "852us",
-    "p99_latency": "3.42ms",
-    "cpu": "6004.9%",
-    "memory": "199MiB",
+    "rps": 882230,
+    "avg_latency": "579us",
+    "p99_latency": "3.55ms",
+    "cpu": "6417.0%",
+    "memory": "220MiB",
     "connections": 512,
     "threads": 64,
     "duration": "5s",
     "pipeline": 1,
-    "bandwidth": "82.73MB/s",
-    "input_bw": "46.55MB/s",
+    "bandwidth": "121.13MB/s",
+    "input_bw": "68.15MB/s",
     "reconnects": 0,
-    "status_2xx": 3012738,
+    "status_2xx": 4411153,
     "status_3xx": 0,
     "status_4xx": 0,
     "status_5xx": 0

@@ -1133,6 +1133,26 @@
     "status_4xx": 0,
     "status_5xx": 0
   },
+  {
+    "framework": "userver",
+    "language": "C++",
+    "rps": 824264,
+    "avg_latency": "4.90ms",
+    "p99_latency": "11.50ms",
+    "cpu": "6336.2%",
+    "memory": "532MiB",
+    "connections": 4096,
+    "threads": 64,
+    "duration": "5s",
+    "pipeline": 1,
+    "bandwidth": "974.43MB/s",
+    "input_bw": "39.30MB/s",
+    "reconnects": 163267,
+    "status_2xx": 4121324,
+    "status_3xx": 0,
+    "status_4xx": 0,
+    "status_5xx": 0
+  },
   {
     "framework": "uvicorn",
     "language": "Python",

@@ -959,6 +959,26 @@
     "status_4xx": 0,
     "status_5xx": 0
   },
+  {
+    "framework": "userver",
+    "language": "C++",
+    "rps": 485067,
+    "avg_latency": "32.61ms",
+    "p99_latency": "122.40ms",
+    "cpu": "6493.6%",
+    "memory": "1.5GiB",
+    "connections": 16384,
+    "threads": 64,
+    "duration": "5s",
+    "pipeline": 1,
+    "bandwidth": "309.53MB/s",
+    "input_bw": "36.08MB/s",
+    "reconnects": 89322,
+    "status_2xx": 2425337,
+    "status_3xx": 0,
+    "status_4xx": 0,
+    "status_5xx": 0
+  },
   {
     "framework": "uvicorn",
     "language": "Python",

@@ -959,6 +959,26 @@
     "status_4xx": 0,
     "status_5xx": 0
   },
+  {
+    "framework": "userver",
+    "language": "C++",
+    "rps": 495304,
+    "avg_latency": "8.23ms",
+    "p99_latency": "17.50ms",
+    "cpu": "6370.6%",
+    "memory": "556MiB",
+    "connections": 4096,
+    "threads": 64,
+    "duration": "5s",
+    "pipeline": 1,
+    "bandwidth": "316.07MB/s",
+    "input_bw": "36.84MB/s",
+    "reconnects": 97245,
+    "status_2xx": 2476520,
+    "status_3xx": 0,
+    "status_4xx": 0,
+    "status_5xx": 0
+  },
   {
     "framework": "uvicorn",
     "language": "Python",

@@ -959,6 +959,26 @@
     "status_4xx": 0,
     "status_5xx": 0
   },
+  {
+    "framework": "userver",
+    "language": "C++",
+    "rps": 495502,
+    "avg_latency": "1.02ms",
+    "p99_latency": "4.19ms",
+    "cpu": "6541.9%",
+    "memory": "248MiB",
+    "connections": 512,
+    "threads": 64,
+    "duration": "5s",
+    "pipeline": 1,
+    "bandwidth": "316.20MB/s",
+    "input_bw": "36.86MB/s",
+    "reconnects": 99102,
+    "status_2xx": 2477512,
+    "status_3xx": 0,
+    "status_4xx": 0,
+    "status_5xx": 0
+  },
   {
     "framework": "uvicorn",
     "language": "Python",

@@ -1428,19 +1428,19 @@
   {
     "framework": "userver",
     "language": "C++",
-    "rps": 850039,
-    "avg_latency": "4.81ms",
-    "p99_latency": "15.50ms",
-    "cpu": "6090.8%",
-    "memory": "578MiB",
+    "rps": 886892,
+    "avg_latency": "4.63ms",
+    "p99_latency": "12.90ms",
+    "cpu": "6261.2%",
+    "memory": "603MiB",
     "connections": 4096,
     "threads": 64,
     "duration": "5s",
     "pipeline": 1,
-    "bandwidth": "116.69MB/s",
-    "input_bw": "65.66MB/s",
-    "reconnects": 423697,
-    "status_2xx": 4250195,
+    "bandwidth": "121.75MB/s",
+    "input_bw": "68.51MB/s",
+    "reconnects": 441759,
+    "status_2xx": 4434464,
     "status_3xx": 0,
     "status_4xx": 0,
     "status_5xx": 0

@@ -1428,19 +1428,19 @@
   {
     "framework": "userver",
     "language": "C++",
-    "rps": 701718,
-    "avg_latency": "720us",
+    "rps": 736506,
+    "avg_latency": "686us",
     "p99_latency": "3.98ms",
-    "cpu": "5875.4%",
-    "memory": "240MiB",
+    "cpu": "6086.3%",
+    "memory": "246MiB",
     "connections": 512,
     "threads": 64,
     "duration": "5s",
     "pipeline": 1,
-    "bandwidth": "96.34MB/s",
-    "input_bw": "54.21MB/s",
-    "reconnects": 350772,
-    "status_2xx": 3508594,
+    "bandwidth": "101.12MB/s",
+    "input_bw": "56.89MB/s",
+    "reconnects": 368248,
+    "status_2xx": 3682530,
     "status_3xx": 0,
     "status_4xx": 0,
     "status_5xx": 0