OCT-2282: Lowering the db connection pool size & adding settings for …

…it (#594)

## Description

To better handle the pool size of postgres we lowered the pool size from
100 and moved params to dedicated config.
The issue probably is due to the fact that pg has (default) 100
connection and pool size of sqlalchemy was equal to it, causing
overflows / connection drops because of reached limit.

backend/app/settings.py

@@ -91,7 +91,7 @@ class ProdConfig(Config):
         os.getenv("SQLALCHEMY_CONNECTION_POOL_SIZE", 10)
     )
     SQLALCHEMY_CONNECTION_POOL_MAX_OVERFLOW = int(
-        os.getenv("SQLALCHEMY_CONNECTION_POOL_MAX_OVERFLOW", 100)
+        os.getenv("SQLALCHEMY_CONNECTION_POOL_MAX_OVERFLOW", 0)
     )
     SQLALCHEMY_DATABASE_URI = os.getenv("DB_URI")
     SQLALCHEMY_ENGINE_OPTIONS = {

backend/v2/core/dependencies.py

@@ -36,6 +36,12 @@ def get_w3(
 
 class DatabaseSettings(OctantSettings):
     db_uri: str = Field(..., alias="db_uri")
+
+    pg_pool_size: int = Field(10, alias="sqlalchemy_connection_pool_size")
+    pg_max_overflow: int = Field(0, alias="sqlalchemy_connection_pool_max_overflow")
+    pg_pool_timeout: int = 60
+    pg_pool_recycle: int = 30 * 60  # 30 minutes
+    pg_pool_pre_ping: bool = True
     # TODO other settings of the database
 
     @property
@@ -60,11 +66,11 @@ def get_sessionmaker(
     kw = {}
     if "postgresql" in settings.sqlalchemy_database_uri:
         kw = {
-            "pool_size": 100,  # Initial pool size (default is 5)
-            "max_overflow": 10,  # Extra connections if pool is exhausted
-            "pool_timeout": 30,  # Timeout before giving up on a connection
-            "pool_recycle": 3600,  # Recycle connections after 1 hour (for long-lived connections)
-            "pool_pre_ping": True,  # Check if the connection is alive before using it
+            "pool_size": settings.pg_pool_size,
+            "max_overflow": settings.pg_max_overflow,
+            "pool_timeout": settings.pg_pool_timeout,
+            "pool_recycle": settings.pg_pool_recycle,
+            "pool_pre_ping": settings.pg_pool_pre_ping,
         }
 
     engine = create_async_engine(