Revert "make load session for heavy, single threaded loads"

This reverts commit dffb495.

Author: nofurtherinformation

backend/app/core/db.py

@@ -9,27 +9,10 @@
     pool_recycle=3600,
 )
 
-load_engine = create_engine(
-    str(settings.SQLALCHEMY_DATABASE_URI),
-    echo=settings.ECHO_DB,
-    pool_pre_ping=True,
-    pool_recycle=0,
-    pool_size=1,
-    timeout=3600,
-)
-
 
 def get_session():
     with Session(engine) as session:
         try:
             yield session
         finally:
             session.close()
-
-
-def get_load_session():
-    with Session(load_engine) as session:
-        try:
-            yield session
-        finally:
-            session.close()

backend/management/load_data.py

@@ -11,7 +11,7 @@
     add_districtr_map_to_map_group,
 )
 from app.core.io import get_local_or_s3_path
-from app.core.db import get_load_session
+from app.main import get_session
 from app.core.config import settings
 from functools import wraps
 import logging
@@ -230,7 +230,7 @@ def load_sample_data(
         if skip_gerrydb_loads:
             continue
 
-        session = next(get_load_session())
+        session = next(get_session())
         gpkg = os.path.join(data_dir, view.gpkg)
 
         if not Path(gpkg).exists():
@@ -263,7 +263,7 @@ def load_sample_data(
         logger.info(f"Graph saved to {out_path}")
 
     for view in config._shatterable_views:
-        session = next(get_load_session())
+        session = next(get_session())
         gerrydb_table_exists = session.execute(
             sa.text("select 1 from gerrydbtable where name = :name limit 1"),
             {"name": view.gerrydb_table_name},
@@ -276,18 +276,18 @@ def load_sample_data(
             session.commit()
 
     for view in config._districtr_maps:
-        session = next(get_load_session())
+        session = next(get_session())
         districtr_map_exists = session.execute(
             sa.text(
                 "select uuid from districtrmap where districtr_map_slug = :slug limit 1"
             ),
             {"slug": view.districtr_map_slug},
         ).one_or_none()
+        session.rollback()
         if districtr_map_exists:
             u = districtr_map_exists.uuid
             logger.info(f"Districtr map {view.districtr_map_slug} already exists.")
         else:
-            session = next(get_load_session())
             u = _create_districtr_map(
                 session=session,
                 name=view.name,
@@ -305,7 +305,7 @@ def load_sample_data(
         if u is not None:
             logger.info(f"Created districtr map with UUID {u}")
         else:
-            session = next(get_load_session())
+            session = next(get_session())
             u = session.exec(
                 sa.select(DistrictrMap.uuid).where(  # pyright: ignore
                     DistrictrMap.districtr_map_slug == view.districtr_map_slug
@@ -325,7 +325,7 @@ def load_sample_data(
         session.commit()
 
     for group in config._map_groups:
-        session = next(get_load_session())
+        session = next(get_session())
         add_districtr_map_to_map_group(
             session=session,
             districtr_map_slug=group.districtr_map_slug,