diff --git a/lib/galaxy/model/__init__.py b/lib/galaxy/model/__init__.py
index 9495b3a82401..337e5cf7791a 100644
--- a/lib/galaxy/model/__init__.py
+++ b/lib/galaxy/model/__init__.py
@@ -7727,7 +7727,7 @@ class WorkflowStep(Base, RepresentById):
     uuid = Column(UUIDType)
     label = Column(Unicode(255))
     temp_input_connections: Optional[InputConnDictType]
-    parent_comment_id = Column(Integer, ForeignKey("workflow_comment.id"), nullable=True)
+    parent_comment_id = Column(Integer, ForeignKey("workflow_comment.id"), index=True, nullable=True)
 
     parent_comment = relationship(
         "WorkflowComment",
@@ -8174,7 +8174,7 @@ class WorkflowComment(Base, RepresentById):
     type = Column(String(16))
     color = Column(String(16))
     data = Column(JSONType)
-    parent_comment_id = Column(Integer, ForeignKey("workflow_comment.id"), nullable=True)
+    parent_comment_id = Column(Integer, ForeignKey("workflow_comment.id"), index=True, nullable=True)
 
     workflow = relationship(
         "Workflow",