fix: too many clients sql error

Author: glichtner

execution_engine/converter/parser/fhir_parser_v1.py

@@ -79,6 +79,9 @@ def parse_time_from_event(
 
         new_combo = converter.to_temporal_combination(combo)
 
+        if not isinstance(new_combo, CriterionCombination):
+            raise ValueError(f"Expected CriterionCombination, got {type(new_combo)}")
+
         return new_combo
 
     def parse_characteristics(self, ev: EvidenceVariable) -> CriterionCombination:

execution_engine/omop/sqlclient.py

@@ -4,7 +4,7 @@
 
 import pandas as pd
 import sqlalchemy
-from sqlalchemy import and_, bindparam, event, func, select, text
+from sqlalchemy import NullPool, and_, bindparam, event, func, select, text
 from sqlalchemy.engine.interfaces import DBAPIConnection
 from sqlalchemy.pool import ConnectionPoolEntry
 from sqlalchemy.sql import Insert, Select
@@ -83,6 +83,7 @@ def __init__(
         result_schema: str,
         timezone: str = "Europe/Berlin",
         disable_triggers: bool = False,
+        null_pool: bool = False,
     ) -> None:
         """Initialize the OMOP SQL client."""
 
@@ -97,6 +98,9 @@ def __init__(
             connection_string,
             connect_args={"options": "-csearch_path={}".format(self._data_schema)},
             future=True,
+            poolclass=(
+                NullPool if null_pool else None
+            ),  # <--- ensures no persistent pool
         )
 
         if disable_triggers:

execution_engine/task/task.py

@@ -27,6 +27,7 @@ def get_engine() -> OMOPSQLClient:
     return OMOPSQLClient(
         **get_config().omop.model_dump(by_alias=True),
         timezone=get_config().timezone,
+        null_pool=True,
     )