diff --git a/.github/scripts/query-regression-run.py b/.github/scripts/query-regression-run.py
index 6da7c896d67..d488cee1594 100644
--- a/.github/scripts/query-regression-run.py
+++ b/.github/scripts/query-regression-run.py
@@ -45,6 +45,11 @@ DEFAULT_CASES = [
 
 HEAVY_CASES = [
     "tests/perf/query_cases/prom_remote_write_7913/case.toml",
+    # High-cardinality direct-SST cases exceed the default query-regression
+    # runner's resources (the self-hosted runner is repeatedly lost during the
+    # run). Keep them in the heavy set so they only run on demand.
+    "tests/perf/query_cases/promql_constant_tag_concat_ms_10k/case.toml",
+    "tests/perf/query_cases/promql_constant_tag_concat_ms_100k/case.toml",
 ]
 
 CASE_GROUPS = {
diff --git a/tests/perf/test_query_regression_case_selection.py b/tests/perf/test_query_regression_case_selection.py
index 04a542e23ad..16ba7261428 100644
--- a/tests/perf/test_query_regression_case_selection.py
+++ b/tests/perf/test_query_regression_case_selection.py
@@ -51,10 +51,14 @@ class QueryRegressionCaseSelectionTest(unittest.TestCase):
         self.assertEqual(len(runner.DEFAULT_CASES), 9)
         self.assertEqual(runner.split_cases([]), runner.DEFAULT_CASES)
 
-    def test_heavy_selects_only_remote_write_7913(self) -> None:
+    def test_heavy_selects_the_heavy_case_set(self) -> None:
         self.assertEqual(
             runner.split_cases(["heavy"]),
-            ["tests/perf/query_cases/prom_remote_write_7913/case.toml"],
+            [
+                "tests/perf/query_cases/prom_remote_write_7913/case.toml",
+                "tests/perf/query_cases/promql_constant_tag_concat_ms_10k/case.toml",
+                "tests/perf/query_cases/promql_constant_tag_concat_ms_100k/case.toml",
+            ],
         )
 
     def test_explicit_paths_remain_selectable(self) -> None: