perf(proxy): total a short grouped log page from the page itself

A cursorless page that comes back without its lookahead row is the end of the
list, so the total is offset + len(page) and the bounded grouped COUNT over the
whole spend-log table is skipped. First pages on small deployments and every
offset last page now cost one query less.

Moves the count into _count_grouped_sessions and reworks the query-optimization
test that asserted the count always runs second onto a full page, where it does.

Claude-Session: https://claude.ai/code/session_01ESi9JwaXDww1vP3Qsrr4Mz

litellm/proxy/spend_tracking/spend_management_endpoints.py

@@ -2925,6 +2925,32 @@ async def _fetch_session_representatives(
     return [rep_by_key[key] for key in session_keys if key in rep_by_key]  # mutable-ok: rows are enriched in place
 
 
+async def _count_grouped_sessions(
+    prisma_client: "PrismaClient",
+    where_clause: str,
+    sql_params: Sequence[object],
+    next_param_index: int,
+) -> tuple[int, bool]:
+    """Count the sessions matching the filter, returning ``(total, total_is_capped)`` bounded by the count cap."""
+    count_query: Final = f"""
+        SELECT COUNT(*) AS total_count
+        FROM (
+            SELECT 1
+            FROM "LiteLLM_SpendLogs"
+            WHERE {where_clause}
+            GROUP BY {_SESSION_GROUP_KEY_SQL}
+            LIMIT ${next_param_index}
+        ) AS bounded_sessions
+    """
+    count_rows: Final[Sequence[_SpendLogsCountRow]] = await _query_raw(
+        prisma_client, count_query, *sql_params, SPEND_LOGS_PAGINATION_COUNT_CAP + 1
+    )
+    raw_total: Final = int(count_rows[0]["total_count"]) if count_rows else 0
+    return (
+        (SPEND_LOGS_PAGINATION_COUNT_CAP, True) if raw_total > SPEND_LOGS_PAGINATION_COUNT_CAP else (raw_total, False)
+    )
+
+
 async def _ui_session_grouped_spend_logs(
     prisma_client: "PrismaClient",
     sql_conditions: Sequence[str],
@@ -2953,7 +2979,9 @@ async def _ui_session_grouped_spend_logs(
     by its newest non-MCP row, enriched by ``_build_ui_spend_logs_response``
     exactly like the flat listing, and the response carries
     ``next_session_cursor`` / ``has_more`` while ``total`` counts sessions
-    (capped like the flat total).
+    (capped like the flat total). A page that runs out of sessions is itself
+    the end of the list, so its ``total`` is ``offset + len(page)`` and the
+    grouped count query is skipped.
     """
     where_clause: Final = " AND ".join(sql_conditions) if sql_conditions else "TRUE"
     cmp_op: Final = "<" if sort_desc else ">"
@@ -2998,22 +3026,12 @@ async def _ui_session_grouped_spend_logs(
         else None
     )
 
-    count_query: Final = f"""
-        SELECT COUNT(*) AS total_count
-        FROM (
-            SELECT 1
-            FROM "LiteLLM_SpendLogs"
-            WHERE {where_clause}
-            GROUP BY {_SESSION_GROUP_KEY_SQL}
-            LIMIT ${next_param_index}
-        ) AS bounded_sessions
-    """
-    count_rows: Final[Sequence[_SpendLogsCountRow]] = await _query_raw(
-        prisma_client, count_query, *sql_params, SPEND_LOGS_PAGINATION_COUNT_CAP + 1
+    page_ends_the_list: Final = cursor is None and page_limit > 0 and not has_more
+    total_records, total_is_capped = (
+        (offset + len(page_rows), False)
+        if page_ends_the_list
+        else await _count_grouped_sessions(prisma_client, where_clause, sql_params, next_param_index)
     )
-    raw_total: Final = int(count_rows[0]["total_count"]) if count_rows else 0
-    total_is_capped: Final = raw_total > SPEND_LOGS_PAGINATION_COUNT_CAP
-    total_records: Final = SPEND_LOGS_PAGINATION_COUNT_CAP if total_is_capped else raw_total
 
     session_keys: Final = tuple((row["session_key"], row["api_key"]) for row in visible_rows)
     data: Final[list[dict[str, object]]] = (  # mutable-ok: _build_ui_spend_logs_response writes onto each row

tests/test_litellm/proxy/spend_tracking/test_spend_management_endpoints.py

@@ -6629,12 +6629,12 @@ def _session_page_row(session_key, last_activity):
     return {"session_key": session_key, "api_key": "hashed-key", "last_activity": last_activity}
 
 
-def _session_grouped_paginating_prisma(sessions):
+def _session_grouped_paginating_prisma(sessions, counted_total=None):
     """Mock prisma serving the grouped page query out of ``sessions``, honoring the LIMIT and OFFSET it asks for."""
 
     async def mock_query_raw(sql_query, *params):
         if "COUNT(*) AS total_count" in sql_query:
-            return [{"total_count": min(len(sessions), params[-1])}]
+            return [{"total_count": min(len(sessions) if counted_total is None else counted_total, params[-1])}]
         if "DISTINCT ON" in sql_query:
             return [_session_representative_row(f"req-{session_key}", session_key) for session_key in params[-2]]
         if "COALESCE(SUM(spend)" in sql_query:
@@ -6803,6 +6803,42 @@ async def test_ui_view_spend_logs_group_by_session_jumps_to_page_without_cursor(
         app.dependency_overrides.pop(ps.user_api_key_auth, None)
 
 
+@pytest.mark.asyncio
+async def test_ui_view_spend_logs_group_by_session_short_page_totals_itself(client, monkeypatch):
+    """A page that runs out of sessions is the end of the list, so the total comes from it and nothing is counted."""
+    sessions = tuple((f"sess-{index:02d}", f"2026-08-29 10:{59 - index:02d}:00") for index in range(10))
+    mock_prisma = _session_grouped_paginating_prisma(sessions, counted_total=999)
+    monkeypatch.setattr("litellm.proxy.proxy_server.prisma_client", mock_prisma)
+    monkeypatch.setattr(
+        "litellm.proxy.spend_tracking.spend_management_endpoints._is_admin_view_safe",
+        lambda user_api_key_dict: True,
+    )
+    app.dependency_overrides[ps.user_api_key_auth] = lambda: UserAPIKeyAuth(
+        user_role=LitellmUserRoles.PROXY_ADMIN, user_id="admin_user"
+    )
+    try:
+        start_date, end_date = _default_date_range()
+        response = client.get(
+            "/spend/logs/ui",
+            params={
+                "start_date": start_date,
+                "end_date": end_date,
+                "group_by_session": "true",
+                "page": 1,
+                "page_size": 25,
+            },
+            headers={"Authorization": "Bearer sk-test"},
+        )
+        assert response.status_code == 200, response.text
+        data = response.json()
+        assert data["total"] == 10, "the count query's 999 would have won if it had been asked"
+        assert data["total_is_capped"] is False
+        assert data["total_pages"] == 1
+        assert len(data["data"]) == 10
+    finally:
+        app.dependency_overrides.pop(ps.user_api_key_auth, None)
+
+
 @pytest.mark.asyncio
 async def test_ui_view_spend_logs_group_by_session_page_past_count_cap_is_empty(client, monkeypatch):
     """The last page inside the capped total still lists sessions; the page after it is empty and costs no query."""

tests/test_litellm/proxy/spend_tracking/test_spend_query_optimization.py

@@ -528,8 +528,8 @@ async def test_spend_logs_ui_group_by_session_paginates_sessions(monkeypatch):
 
     group_key = "COALESCE(NULLIF(session_id, ''), request_id), api_key"
     session_rows = [
-        {"session_key": "req-1", "api_key": "k", "last_activity": "2026-02-16 10:00:00"},
-        {"session_key": "req-2", "api_key": "k", "last_activity": "2026-02-16 09:00:00"},
+        {"session_key": f"req-{index}", "api_key": "k", "last_activity": f"2026-02-16 10:{59 - index:02d}:00"}
+        for index in range(51)
     ]
     representative_rows = [
         {"request_id": "req-1", "api_key": "k", "metadata": "{}", "session_id": None},
@@ -538,7 +538,7 @@ async def test_spend_logs_ui_group_by_session_paginates_sessions(monkeypatch):
 
     async def mock_query_raw(sql_query, *params):
         if "COUNT(*) AS total_count" in sql_query:
-            return [{"total_count": 12}]
+            return [{"total_count": 60}]
         if "DISTINCT ON" in sql_query:
             return representative_rows
         return session_rows
@@ -590,11 +590,11 @@ async def test_spend_logs_ui_group_by_session_paginates_sessions(monkeypatch):
     assert "COUNT(*) OVER ()" not in rep_sql
 
     assert [row["request_id"] for row in response["data"]] == ["req-1", "req-2"]
-    assert response["total"] == 12
+    assert response["total"] == 60
     assert response["total_is_capped"] is False
-    assert response["total_pages"] == 1
-    assert response["has_more"] is False
-    assert response["next_session_cursor"] is None
+    assert response["total_pages"] == 2
+    assert response["has_more"] is True
+    assert response["next_session_cursor"] == "2026-02-16 10:10:00|k|req-49"
 
 
 @pytest.mark.asyncio