Reduce detail concurrency for two-core VPS

docker-compose.yml

@@ -101,7 +101,7 @@ services:
     environment:
       POLYWEATHER_REDIS_URL: ${POLYWEATHER_REDIS_URL:-redis://polyweather_redis:6379/0}
       POLYWEATHER_COLLECTOR_PATCH_ENDPOINT: ''
-      POLYWEATHER_CITY_DETAIL_BATCH_CONCURRENCY: ${POLYWEATHER_CITY_DETAIL_BATCH_CONCURRENCY:-2}
+      POLYWEATHER_CITY_DETAIL_BATCH_CONCURRENCY: ${POLYWEATHER_CITY_DETAIL_BATCH_CONCURRENCY:-1}
       POLYWEATHER_CITY_DETAIL_BATCH_GLOBAL_CONCURRENCY: ${POLYWEATHER_CITY_DETAIL_BATCH_GLOBAL_CONCURRENCY:-1}
       POLYWEATHER_CITY_DETAIL_BATCH_QUEUE_WAIT_MS: ${POLYWEATHER_CITY_DETAIL_BATCH_QUEUE_WAIT_MS:-3000}
       POLYWEATHER_CITY_DETAIL_BATCH_PARTIAL_TIMEOUT_MS: ${POLYWEATHER_CITY_DETAIL_BATCH_PARTIAL_TIMEOUT_MS:-8000}
@@ -114,7 +114,7 @@ services:
       POLYWEATHER_OBSERVATION_COLLECTOR_MADIS_SEC: ${POLYWEATHER_OBSERVATION_COLLECTOR_MADIS_SEC:-300}
       POLYWEATHER_OBSERVATION_COLLECTOR_TICK_SEC: ${POLYWEATHER_OBSERVATION_COLLECTOR_TICK_SEC:-30}
       POLYWEATHER_SCAN_TERMINAL_BUILD_TIMEOUT_SEC: '30'
-      POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS: ${POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS:-2}
+      POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS: ${POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS:-1}
       POLYWEATHER_SCAN_TERMINAL_PREWARM_ENABLED: 'false'
       POLYWEATHER_SERVICE_ROLE: web
       UVICORN_WORKERS: ${UVICORN_WORKERS:-2}

tests/test_deployment_runtime_config.py

@@ -93,12 +93,12 @@ def test_docker_compose_isolates_collector_from_web_and_bot_services():
     assert "POLYWEATHER_SCAN_TERMINAL_PREWARM_ENABLED: 'false'" in bot_block
     assert "POLYWEATHER_SCAN_TERMINAL_PREWARM_ENABLED: 'false'" in web_block
     assert "POLYWEATHER_SCAN_TERMINAL_BUILD_TIMEOUT_SEC: '30'" in web_block
-    assert "POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS: ${POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS:-2}" in web_block
+    assert "POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS: ${POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS:-1}" in web_block
     assert "POLYWEATHER_SCAN_TERMINAL_PREWARM_ENABLED: 'false'" in collector_block
     assert "POLYWEATHER_OBSERVATION_COLLECTOR_ENABLED: 'false'" in bot_block
     assert "POLYWEATHER_OBSERVATION_COLLECTOR_ENABLED: 'false'" in web_block
     assert "POLYWEATHER_OBSERVATION_COLLECTOR_ENABLED: 'true'" in collector_block
-    assert "POLYWEATHER_CITY_DETAIL_BATCH_CONCURRENCY: ${POLYWEATHER_CITY_DETAIL_BATCH_CONCURRENCY:-2}" in web_block
+    assert "POLYWEATHER_CITY_DETAIL_BATCH_CONCURRENCY: ${POLYWEATHER_CITY_DETAIL_BATCH_CONCURRENCY:-1}" in web_block
     assert "POLYWEATHER_CITY_DETAIL_BATCH_GLOBAL_CONCURRENCY: ${POLYWEATHER_CITY_DETAIL_BATCH_GLOBAL_CONCURRENCY:-1}" in web_block
     assert "POLYWEATHER_CITY_DETAIL_BATCH_QUEUE_WAIT_MS: ${POLYWEATHER_CITY_DETAIL_BATCH_QUEUE_WAIT_MS:-3000}" in web_block
     assert "POLYWEATHER_CITY_DETAIL_BATCH_PARTIAL_TIMEOUT_MS: ${POLYWEATHER_CITY_DETAIL_BATCH_PARTIAL_TIMEOUT_MS:-8000}" in web_block
@@ -128,7 +128,7 @@ def test_scan_terminal_backend_timeout_returns_before_next_proxy_abort():
 
     assert 'POLYWEATHER_SCAN_TERMINAL_PROXY_TIMEOUT_MS || "35000"' in route_source
     assert '"POLYWEATHER_SCAN_TERMINAL_BUILD_TIMEOUT_SEC",\n    30,' in config_source
-    assert '"POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS",\n    2,' in config_source
+    assert '"POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS",\n    1,' in config_source
     assert (
         '"POLYWEATHER_SCAN_TERMINAL_PREWARM_PAYLOAD_TIMEOUT_SEC",\n    30,'
         in config_source

tests/test_web_observability.py

@@ -1063,7 +1063,7 @@ def test_city_detail_batch_partial_timeout_default_stays_below_proxy_budget(monk
     monkeypatch.delenv("POLYWEATHER_CITY_DETAIL_BATCH_GLOBAL_CONCURRENCY", raising=False)
     monkeypatch.delenv("POLYWEATHER_CITY_DETAIL_BATCH_QUEUE_WAIT_MS", raising=False)
 
-    assert city_api._city_detail_batch_concurrency() == 2
+    assert city_api._city_detail_batch_concurrency() == 1
     assert city_api._city_detail_batch_global_concurrency() == 1
     assert city_api._city_detail_batch_queue_wait_seconds() == 3.0
     assert city_api._city_detail_batch_partial_timeout_seconds() == 8.0

web/services/city_api.py

@@ -987,9 +987,9 @@ async def _build_city_detail_batch_item_async(
 
 def _city_detail_batch_concurrency() -> int:
     try:
-        value = int(os.getenv("POLYWEATHER_CITY_DETAIL_BATCH_CONCURRENCY", "2") or "2")
+        value = int(os.getenv("POLYWEATHER_CITY_DETAIL_BATCH_CONCURRENCY", "1") or "1")
     except ValueError:
-        value = 2
+        value = 1
     return max(1, min(4, value))
 
 

web/services/scan_terminal_config.py

@@ -43,7 +43,7 @@ SCAN_TERMINAL_PREWARM_PAYLOAD_TIMEOUT_SEC = _env_int(
 )
 SCAN_TERMINAL_MAX_WORKERS = _env_int(
     "POLYWEATHER_SCAN_TERMINAL_MAX_WORKERS",
-    2,
+    1,
     min_value=1,
     max_value=12,
 )