refactor: Increase database connection pool

Author: XiaJunjie2020

backend/common/core/config.py

@@ -92,5 +92,10 @@ def SQLALCHEMY_DATABASE_URI(self) -> PostgresDsn | str:
     EMBEDDING_SIMILARITY: float = 0.4
     EMBEDDING_TOP_COUNT: int = 5
 
+    PG_POOL_SIZE: int = 20
+    PG_MAX_OVERFLOW: int = 30
+    PG_POOL_RECYCLE: int = 3600
+    PG_POOL_PRE_PING: bool = True
+
 
 settings = Settings()  # type: ignore

backend/common/core/db.py

@@ -2,8 +2,11 @@
 
 from common.core.config import settings
 
-engine = create_engine(str(settings.SQLALCHEMY_DATABASE_URI), pool_size=20, max_overflow=30, pool_recycle=3600,
-                       pool_pre_ping=True)
+engine = create_engine(str(settings.SQLALCHEMY_DATABASE_URI),
+                       pool_size=settings.PG_POOL_SIZE,
+                       max_overflow=settings.PG_MAX_OVERFLOW,
+                       pool_recycle=settings.PG_POOL_RECYCLE,
+                       pool_pre_ping=settings.PG_POOL_PRE_PING)
 
 
 def get_session():