database optimization/ back button in the configurator/ query competition and more

database/db.py

@@ -1,15 +1,24 @@
+import asyncio
+
+from sqlalchemy import text
 from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
 from sqlalchemy.orm import declarative_base
 
-from config import DATABASE_URL
+from config import DATABASE_URL, DB_MAX_OVERFLOW, DB_POOL_SIZE
+
+
+CONCURRENT_UPDATES_LIMIT = DB_POOL_SIZE + DB_MAX_OVERFLOW
+MAX_UPDATE_AGE_SEC = 28
 
 engine = create_async_engine(
     DATABASE_URL,
     echo=False,
     future=True,
-    pool_size=100,
-    max_overflow=200,
+    pool_size=DB_POOL_SIZE,
+    max_overflow=DB_MAX_OVERFLOW,
     pool_timeout=60,
+    pool_pre_ping=True,
+    pool_recycle=300,
 )
 
 async_session_maker = async_sessionmaker(
@@ -19,3 +28,20 @@ async_session_maker = async_sessionmaker(
 )
 
 Base = declarative_base()
+
+WARM_POOL_COUNT = 10
+
+
+async def warm_pool() -> None:
+    """
+    Прогревает пул соединений при старте.
+    """
+
+    async def _one() -> None:
+        async with async_session_maker() as session:
+            await session.execute(text("SELECT 1"))
+
+    count = min(WARM_POOL_COUNT, DB_POOL_SIZE)
+    if count <= 0:
+        return
+    await asyncio.gather(*[asyncio.create_task(_one()) for _ in range(count)])