fix(workbench-runtime): ensure session read indexes

internal/workbenchruntime/service.go

@@ -34,6 +34,12 @@ type Server struct {
 	mux    *http.ServeMux
 }
 
+var workbenchRuntimeReadIndexes = []string{
+	"CREATE INDEX IF NOT EXISTS idx_workbench_sessions_updated ON workbench_sessions(updated_at DESC, session_id)",
+	"CREATE INDEX IF NOT EXISTS idx_workbench_sessions_owner_updated ON workbench_sessions(owner_user_id, updated_at DESC, session_id)",
+	"CREATE INDEX IF NOT EXISTS idx_workbench_sessions_status_updated ON workbench_sessions(status, updated_at DESC, session_id)",
+}
+
 type factQuery struct {
 	Families           []string `json:"families"`
 	FactFamilies       []string `json:"factFamilies"`
@@ -120,6 +126,9 @@ func Run(ctx context.Context) error {
 		db.SetMaxOpenConns(config.PoolMax)
 		db.SetMaxIdleConns(config.PoolMax)
 	}
+	if err := ensureWorkbenchRuntimeReadIndexes(ctx, db); err != nil {
+		return err
+	}
 	server := NewServer(config, db)
 	httpServer := &http.Server{Addr: config.Addr, Handler: server.otelHTTPHandler(server.mux), ReadHeaderTimeout: 5 * time.Second}
 	errCh := make(chan error, 1)
@@ -142,6 +151,17 @@ func Run(ctx context.Context) error {
 	return httpServer.Shutdown(shutdownCtx)
 }
 
+func ensureWorkbenchRuntimeReadIndexes(ctx context.Context, db *sql.DB) error {
+	ensureCtx, cancel := context.WithTimeout(ctx, 30*time.Second)
+	defer cancel()
+	for _, statement := range workbenchRuntimeReadIndexes {
+		if _, err := db.ExecContext(ensureCtx, statement); err != nil {
+			return fmt.Errorf("ensure workbench runtime read index: %w", err)
+		}
+	}
+	return nil
+}
+
 func NewServer(config Config, db *sql.DB) *Server {
 	server := &Server{config: config, db: db, mux: http.NewServeMux()}
 	server.routes()
@@ -474,12 +494,7 @@ func (s *Server) queryFactRows(ctx context.Context, table string, jsonColumn str
 
 func (s *Server) queryJSONColumn(ctx context.Context, stage string, table string, sqlText string, args []any) ([]any, error) {
 	result := []any{}
-	err := s.withOtelInternalSpan(ctx, stage, map[string]any{
-		"db.system":          "postgresql",
-		"db.operation.name":  "SELECT",
-		"db.sql.table":       table,
-		"db.query.arg_count": int64(len(args)),
-	}, func(spanCtx context.Context) error {
+	err := s.withOtelInternalSpan(ctx, stage, s.dbQueryAttrs(table, len(args), nil), func(spanCtx context.Context) error {
 		rows, err := s.db.QueryContext(spanCtx, sqlText, args...)
 		if err != nil {
 			return err
@@ -503,14 +518,31 @@ func (s *Server) queryJSONColumn(ctx context.Context, stage string, table string
 	return result, nil
 }
 
+func (s *Server) dbQueryAttrs(table string, argCount int, extra map[string]any) map[string]any {
+	stats := s.db.Stats()
+	attrs := map[string]any{
+		"db.system":                   "postgresql",
+		"db.operation.name":           "SELECT",
+		"db.sql.table":                table,
+		"db.query.arg_count":          int64(argCount),
+		"db.pool.max_open":            int64(s.config.PoolMax),
+		"db.pool.open_connections":    int64(stats.OpenConnections),
+		"db.pool.in_use":              int64(stats.InUse),
+		"db.pool.idle":                int64(stats.Idle),
+		"db.pool.wait_count":          int64(stats.WaitCount),
+		"db.pool.wait_duration_ms":    stats.WaitDuration.Milliseconds(),
+		"db.pool.max_idle_closed":     int64(stats.MaxIdleClosed),
+		"db.pool.max_lifetime_closed": int64(stats.MaxLifetimeClosed),
+	}
+	for key, value := range extra {
+		attrs[key] = value
+	}
+	return attrs
+}
+
 func (s *Server) querySessionSummaries(ctx context.Context, stage string, sqlText string, args []any) ([]any, error) {
 	result := []any{}
-	err := s.withOtelInternalSpan(ctx, stage, map[string]any{
-		"db.system":          "postgresql",
-		"db.operation.name":  "SELECT",
-		"db.sql.table":       "workbench_sessions",
-		"db.query.arg_count": int64(len(args)),
-	}, func(spanCtx context.Context) error {
+	err := s.withOtelInternalSpan(ctx, stage, s.dbQueryAttrs("workbench_sessions", len(args), map[string]any{"db.index.expected": "idx_workbench_sessions_owner_updated|idx_workbench_sessions_updated"}), func(spanCtx context.Context) error {
 		rows, err := s.db.QueryContext(spanCtx, sqlText, args...)
 		if err != nil {
 			return err