add migration to fix bad cached mem values (#1196)

internal/migrations/1758738789_fix_cached_mem.go

@@ -0,0 +1,50 @@
+package migrations
+
+import (
+	"github.com/henrygd/beszel/internal/entities/system"
+	"github.com/pocketbase/pocketbase/core"
+	m "github.com/pocketbase/pocketbase/migrations"
+)
+
+// This can be deleted after Nov 2025 or so
+
+func init() {
+	m.Register(func(app core.App) error {
+		app.RunInTransaction(func(txApp core.App) error {
+			var systemIds []string
+			txApp.DB().NewQuery("SELECT id FROM systems").Column(&systemIds)
+
+			for _, systemId := range systemIds {
+				var statRecordIds []string
+				txApp.DB().NewQuery("SELECT id FROM system_stats WHERE system = {:system} AND created > {:created}").Bind(map[string]any{"system": systemId, "created": "2025-09-21"}).Column(&statRecordIds)
+
+				for _, statRecordId := range statRecordIds {
+					statRecord, err := txApp.FindRecordById("system_stats", statRecordId)
+					if err != nil {
+						return err
+					}
+					var systemStats system.Stats
+					err = statRecord.UnmarshalJSONField("stats", &systemStats)
+					if err != nil {
+						return err
+					}
+					// if mem buff cache is less than total mem, we don't need to fix it
+					if systemStats.MemBuffCache < systemStats.Mem {
+						continue
+					}
+					systemStats.MemBuffCache = 0
+					statRecord.Set("stats", systemStats)
+					err = txApp.SaveNoValidate(statRecord)
+					if err != nil {
+						return err
+					}
+				}
+			}
+
+			return nil
+		})
+		return nil
+	}, func(app core.App) error {
+		return nil
+	})
+}