diff --git a/backend/open_webui/migrations/versions/a7e2c4f91b08_add_pending_knowledge_files_index.py b/backend/open_webui/migrations/versions/a7e2c4f91b08_add_pending_knowledge_files_index.py
new file mode 100644
index 0000000000..991adb64b3
--- /dev/null
+++ b/backend/open_webui/migrations/versions/a7e2c4f91b08_add_pending_knowledge_files_index.py
@@ -0,0 +1,34 @@
+"""add pending knowledge files index
+
+Revision ID: a7e2c4f91b08
+Revises: d4c1a8e37b62
+Create Date: 2026-09-14 13:42:18.905331
+
+"""
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision: str = 'a7e2c4f91b08'
+down_revision: str | None = 'd4c1a8e37b62'
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    # SQLite does not fold bound parameters when matching an expression index, so it could never use this one.
+    if op.get_bind().dialect.name == 'postgresql':
+        op.create_index(
+            'file_pending_knowledge_idx',
+            'file',
+            [sa.text("((meta -> 'data') ->> 'knowledge_id')")],
+            postgresql_where=sa.text("(data ->> 'status') IN ('pending', 'processing')"),
+        )
+
+
+def downgrade() -> None:
+    if op.get_bind().dialect.name == 'postgresql':
+        op.drop_index('file_pending_knowledge_idx', table_name='file')