Do not explicitly begin a new transaction when getting next_hid

There is no transactional state, so it seems unncessary. Not starting an
explicit transaction means sqlalchemy won't flush the current session,
which means we're not committing a HDA/HDCA to the database that doesn't
have a hid yet.

lib/galaxy/managers/collections.py

@@ -341,7 +341,7 @@ class DatasetCollectionManager:
             copy_kwds["element_destination"] = parent  # e.g. a history
         if dataset_instance_attributes is not None:
             copy_kwds["dataset_instance_attributes"] = dataset_instance_attributes
-        new_hdca = source_hdca.copy(**copy_kwds)
+        new_hdca = source_hdca.copy(flush=False, **copy_kwds)
         new_hdca.copy_tags_from(target_user=trans.get_user(), source=source_hdca)
         if not copy_elements:
             parent.add_dataset_collection(new_hdca)

lib/galaxy/model/__init__.py

@@ -2566,10 +2566,9 @@ class History(Base, HasTags, Dictifiable, UsesAnnotations, HasName, RepresentByI
         else:
             hdcas = self.active_dataset_collections
         for hdca in hdcas:
-            new_hdca = hdca.copy()
+            new_hdca = hdca.copy(flush=False)
             new_history.add_dataset_collection(new_hdca, set_hid=False)
             db_session.add(new_hdca)
-            db_session.flush()
 
             if target_user:
                 new_hdca.copy_item_annotation(db_session, self.user, hdca, target_user, new_hdca)
@@ -5699,7 +5698,7 @@ class HistoryDatasetCollectionAssociation(
                 break
         return matching_collection
 
-    def copy(self, element_destination=None, dataset_instance_attributes=None):
+    def copy(self, element_destination=None, dataset_instance_attributes=None, flush=True):
         """
         Create a copy of this history dataset collection association. Copy
         underlying collection.
@@ -5729,7 +5728,7 @@ class HistoryDatasetCollectionAssociation(
         if element_destination:
             element_destination.stage_addition(hdca)
             element_destination.add_pending_items()
-        else:
+        if flush:
             object_session(self).flush()
         return hdca
 

lib/galaxy/model/mapping.py

@@ -45,19 +45,13 @@ def db_next_hid(self, n=1):
     """
     session = object_session(self)
     table = self.table
-    trans = session.begin()
-    try:
-        if "postgres" not in session.bind.dialect.name:
-            next_hid = select([table.c.hid_counter], table.c.id == model.cached_id(self)).with_for_update().scalar()
-            table.update(table.c.id == self.id).execute(hid_counter=(next_hid + n))
-        else:
-            stmt = table.update().where(table.c.id == model.cached_id(self)).values(hid_counter=(table.c.hid_counter + n)).returning(table.c.hid_counter)
-            next_hid = session.execute(stmt).scalar() - n
-        trans.commit()
-        return next_hid
-    except Exception:
-        trans.rollback()
-        raise
+    if "postgres" not in session.bind.dialect.name:
+        next_hid = select([table.c.hid_counter], table.c.id == model.cached_id(self)).with_for_update().scalar()
+        table.update(table.c.id == self.id).execute(hid_counter=(next_hid + n))
+    else:
+        stmt = table.update().where(table.c.id == model.cached_id(self)).values(hid_counter=(table.c.hid_counter + n)).returning(table.c.hid_counter)
+        next_hid = session.execute(stmt).scalar() - n
+    return next_hid
 
 
 model.History._next_hid = db_next_hid  # type: ignore

lib/galaxy/tools/execute.py

@@ -111,18 +111,16 @@ def execute(trans, tool, mapping_params, history, rerun_remap_job_id=None, colle
             history = execution_slice.history or history
             jobs_executed += 1
 
-    if execution_slice:
-        # a side effect of adding datasets to a history is a commit within db_next_hid (even with flush=False).
-        history.add_pending_items()
-    else:
-        # Make sure collections, implicit jobs etc are flushed even if there are no precreated output datasets
-        trans.sa_session.flush()
-
     if job_datasets:
         for job, datasets in job_datasets.items():
             for dataset_instance in datasets:
                 dataset_instance.dataset.job = job
 
+    if execution_slice:
+        history.add_pending_items()
+    # Make sure collections, implicit jobs etc are flushed even if there are no precreated output datasets
+    trans.sa_session.flush()
+
     tool_id = tool.id
     for job in execution_tracker.successful_jobs:
         # Put the job in the queue if tracking in memory

test/unit/tools/test_history_imp_exp.py

@@ -516,6 +516,7 @@ def test_export_copied_objects_copied_outside_history():
 
     other_h = model.History(name=h.name + "-other", user=h.user)
     sa_session.add(other_h)
+    sa_session.flush()
 
     hc3 = hc2.copy(element_destination=other_h)
     other_h.add_pending_items()