Search: load dashboard performance improvements (#57509)

* fix windows storage init

* fixxx

* close session asap

* fix span end

* error handling

* add comment

* simplify

* simplify

* fix limit

* pass readDashboardCtx to summary builder

* add string slice validation

pkg/services/searchV2/index.go

@@ -846,30 +846,101 @@ func (l sqlDashboardLoader) loadAllDashboards(ctx context.Context, limit int, or
 			dashboardQuerySpan.SetAttributes("dashboardUID", dashboardUID, attribute.Key("dashboardUID").String(dashboardUID))
 			dashboardQuerySpan.SetAttributes("lastID", lastID, attribute.Key("lastID").Int64(lastID))
 
-			rows := make([]*dashboardQueryResult, 0)
+			var slices [][]string
 			err := l.sql.WithDbSession(dashboardQueryCtx, func(sess *db.Session) error {
-				sess.Table("dashboard").
-					Where("org_id = ?", orgID)
+				sql := "select id, uid, is_folder, folder_id, slug, data, created, updated from dashboard where org_id = ?"
+				sqlAndArgs := []interface{}{"", orgID}
 
 				if lastID > 0 {
-					sess.Where("id > ?", lastID)
+					sql += " AND id > ?"
+					sqlAndArgs = append(sqlAndArgs, lastID)
 				}
 
 				if dashboardUID != "" {
-					sess.Where("uid = ?", dashboardUID)
+					sql += " AND uid = ?"
+					sqlAndArgs = append(sqlAndArgs, dashboardUID)
 				}
 
-				sess.Cols("id", "uid", "is_folder", "folder_id", "data", "slug", "created", "updated")
+				sql += " order by id asc"
+				sql += " limit ?"
+				sqlAndArgs = append(sqlAndArgs, limit)
 
-				sess.OrderBy("id ASC")
-				sess.Limit(limit)
-
-				return sess.Find(&rows)
+				sqlAndArgs[0] = sql
+				output, err := sess.QuerySliceString(sqlAndArgs...)
+				slices = output
+				return err
 			})
 
+			dashboardQuerySpan.SetAttributes("dashboardCount", len(slices), attribute.Key("dashboardCount").Int(len(slices)))
+
+			if err != nil || slices == nil {
+				dashboardQuerySpan.End()
+				ch <- &dashboardsRes{
+					dashboards: nil,
+					err:        err,
+				}
+				break
+			}
+
+			rows := make([]*dashboardQueryResult, len(slices))
+			var parsingErr error
+			for i := range slices {
+				if len(slices[i]) < 8 {
+					parsingErr = fmt.Errorf("expected the dashboard row at index %d to contain 8 elements, has %d. lastID: %d", i, len(slices[i]), lastID)
+					break
+				}
+
+				id, err := strconv.ParseInt(slices[i][0], 10, 64)
+				if err != nil {
+					parsingErr = err
+					break
+				}
+				uid := slices[i][1]
+				isFolder := false
+				if slices[i][2] == "1" {
+					isFolder = true
+				}
+
+				folderID, err := strconv.ParseInt(slices[i][3], 10, 64)
+				if err != nil {
+					parsingErr = err
+					break
+				}
+
+				// xorm/session_query.go::value2String() uses `time.RFC3339Nano` to format the time type
+				created, err := time.Parse(time.RFC3339Nano, slices[i][6])
+				if err != nil {
+					parsingErr = err
+					break
+				}
+				updated, err := time.Parse(time.RFC3339Nano, slices[i][7])
+				if err != nil {
+					parsingErr = err
+					break
+				}
+
+				rows[i] = &dashboardQueryResult{
+					Id:       id,
+					Uid:      uid,
+					IsFolder: isFolder,
+					FolderID: folderID,
+					Slug:     slices[i][4],
+					Data:     []byte(slices[i][5]),
+					Created:  created,
+					Updated:  updated,
+				}
+			}
+
 			dashboardQuerySpan.End()
+			if parsingErr != nil {
+				ch <- &dashboardsRes{
+					dashboards: nil,
+					err:        parsingErr,
+				}
+				break
+			}
 
-			if err != nil || len(rows) < limit || dashboardUID != "" {
+			if len(rows) < limit || dashboardUID != "" {
 				ch <- &dashboardsRes{
 					dashboards: rows,
 					err:        err,
@@ -939,7 +1010,7 @@ func (l sqlDashboardLoader) LoadDashboards(ctx context.Context, orgID int64, das
 	for {
 		res, ok := <-dashboardsChannel
 		if res != nil && res.err != nil {
-			l.logger.Error("Error when loading dashboards", "error", err, "orgID", orgID, "dashboardUID", dashboardUID)
+			l.logger.Error("Error when loading dashboards", "error", res.err, "orgID", orgID, "dashboardUID", dashboardUID)
 			break
 		}
 
@@ -949,14 +1020,14 @@ func (l sqlDashboardLoader) LoadDashboards(ctx context.Context, orgID int64, das
 
 		rows := res.dashboards
 
-		_, readDashboardSpan := l.tracer.Start(ctx, "sqlDashboardLoader readDashboard")
+		readDashboardCtx, readDashboardSpan := l.tracer.Start(ctx, "sqlDashboardLoader readDashboard")
 		readDashboardSpan.SetAttributes("orgID", orgID, attribute.Key("orgID").Int64(orgID))
 		readDashboardSpan.SetAttributes("dashboardCount", len(rows), attribute.Key("dashboardCount").Int(len(rows)))
 
 		reader := kdash.NewStaticDashboardSummaryBuilder(lookup, false)
 
 		for _, row := range rows {
-			summary, _, err := reader(ctx, row.Uid, row.Data)
+			summary, _, err := reader(readDashboardCtx, row.Uid, row.Data)
 			if err != nil {
 				l.logger.Warn("Error indexing dashboard data", "error", err, "dashboardId", row.Id, "dashboardSlug", row.Slug)
 				// But append info anyway for now, since we possibly extracted useful information.