diff --git a/backend/alembic/versions/5b29123cd710_nullable_search_settings_for_historic_.py b/backend/alembic/versions/5b29123cd710_nullable_search_settings_for_historic_.py
new file mode 100644
index 000000000..58164cd4c
--- /dev/null
+++ b/backend/alembic/versions/5b29123cd710_nullable_search_settings_for_historic_.py
@@ -0,0 +1,70 @@
+"""nullable search settings for historic index attempts
+
+Revision ID: 5b29123cd710
+Revises: 949b4a92a401
+Create Date: 2024-10-30 19:37:59.630704
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "5b29123cd710"
+down_revision = "949b4a92a401"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # Drop the existing foreign key constraint
+    op.drop_constraint(
+        "fk_index_attempt_search_settings", "index_attempt", type_="foreignkey"
+    )
+
+    # Modify the column to be nullable
+    op.alter_column(
+        "index_attempt", "search_settings_id", existing_type=sa.INTEGER(), nullable=True
+    )
+
+    # Add back the foreign key with ON DELETE SET NULL
+    op.create_foreign_key(
+        "fk_index_attempt_search_settings",
+        "index_attempt",
+        "search_settings",
+        ["search_settings_id"],
+        ["id"],
+        ondelete="SET NULL",
+    )
+
+
+def downgrade() -> None:
+    # Warning: This will delete all index attempts that don't have search settings
+    op.execute(
+        """
+        DELETE FROM index_attempt
+        WHERE search_settings_id IS NULL
+    """
+    )
+
+    # Drop foreign key constraint
+    op.drop_constraint(
+        "fk_index_attempt_search_settings", "index_attempt", type_="foreignkey"
+    )
+
+    # Modify the column to be not nullable
+    op.alter_column(
+        "index_attempt",
+        "search_settings_id",
+        existing_type=sa.INTEGER(),
+        nullable=False,
+    )
+
+    # Add back the foreign key without ON DELETE SET NULL
+    op.create_foreign_key(
+        "fk_index_attempt_search_settings",
+        "index_attempt",
+        "search_settings",
+        ["search_settings_id"],
+        ["id"],
+    )
diff --git a/backend/danswer/background/indexing/run_indexing.py b/backend/danswer/background/indexing/run_indexing.py
index d95a6a70d..252309e3f 100644
--- a/backend/danswer/background/indexing/run_indexing.py
+++ b/backend/danswer/background/indexing/run_indexing.py
@@ -118,7 +118,13 @@ def _run_indexing(
     """
     start_time = time.time()
 
+    if index_attempt.search_settings is None:
+        raise ValueError(
+            "Search settings must be set for indexing. This should not be possible."
+        )
+
     search_settings = index_attempt.search_settings
+
     index_name = search_settings.index_name
 
     # Only update cc-pair status for primary index jobs
diff --git a/backend/danswer/db/models.py b/backend/danswer/db/models.py
index bee693534..3f63d1d0d 100644
--- a/backend/danswer/db/models.py
+++ b/backend/danswer/db/models.py
@@ -734,9 +734,10 @@ class IndexAttempt(Base):
     full_exception_trace: Mapped[str | None] = mapped_column(Text, default=None)
     # Nullable because in the past, we didn't allow swapping out embedding models live
     search_settings_id: Mapped[int] = mapped_column(
-        ForeignKey("search_settings.id"),
-        nullable=False,
+        ForeignKey("search_settings.id", ondelete="SET NULL"),
+        nullable=True,
     )
+
     time_created: Mapped[datetime.datetime] = mapped_column(
         DateTime(timezone=True),
         server_default=func.now(),
@@ -756,7 +757,7 @@ class IndexAttempt(Base):
         "ConnectorCredentialPair", back_populates="index_attempts"
     )
 
-    search_settings: Mapped[SearchSettings] = relationship(
+    search_settings: Mapped[SearchSettings | None] = relationship(
         "SearchSettings", back_populates="index_attempts"
     )