statistics: updating stats cache can trigger evict (pingcap#53979) (pingcap#53991)

close pingcap#53742

Author: ti-chi-bot

pkg/statistics/handle/cache/internal/lfu/BUILD.bazel

@@ -31,7 +31,7 @@ go_test(
     embed = [":lfu"],
     flaky = True,
     race = "on",
-    shard_count = 9,
+    shard_count = 10,
     deps = [
         "//pkg/statistics",
         "//pkg/statistics/handle/cache/internal/testutil",

pkg/statistics/handle/cache/internal/lfu/lfu_cache.go

@@ -206,8 +206,9 @@ func (s *LFU) onExit(val any) {
 	if s.closed.Load() {
 		return
 	}
-	s.addCost(
-		-1 * val.(*statistics.Table).MemoryUsage().TotalTrackingMemUsage())
+	s.triggerEvict()
+	// Subtract the memory usage of the table from the total memory usage.
+	s.addCost(-val.(*statistics.Table).MemoryUsage().TotalTrackingMemUsage())
 }
 
 // Len implements statsCacheInner

pkg/statistics/handle/cache/internal/lfu/lfu_cache_test.go

@@ -306,3 +306,15 @@ func TestMemoryControl(t *testing.T) {
 	lfu.wait()
 	require.Equal(t, int64(10)*(2*mockCMSMemoryUsage+mockCMSMemoryUsage), lfu.Cost())
 }
+
+func TestMemoryControlWithUpdate(t *testing.T) {
+	capacity := int64(100)
+	lfu, err := NewLFU(capacity)
+	require.NoError(t, err)
+	for i := 0; i < 100; i++ {
+		t1 := testutil.NewMockStatisticsTable(i, 1, true, false, false)
+		lfu.Put(1, t1)
+	}
+	time.Sleep(1 * time.Second)
+	require.Equal(t, int64(0), lfu.Cost())
+}