[#902] adm: Do not create session when dumping hashes

Unless the total number of domains is too big, there is no need to
consume resources in neo-go.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

cmd/frostfs-adm/internal/modules/morph/dump_hashes.go

@@ -13,6 +13,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/invoker"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/management"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/unwrap"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
@@ -143,7 +144,12 @@ func dumpCustomZoneHashes(cmd *cobra.Command, nnsHash util.Uint160, zone string,
 		})
 	}
 
-	sessionID, iter, err := unwrap.SessionIterator(inv.Call(nnsHash, "tokens"))
+	script, err := smartcontract.CreateCallAndPrefetchIteratorScript(nnsHash, "tokens", nnsMaxTokens)
+	if err != nil {
+		return fmt.Errorf("create prefetch script: %w", err)
+	}
+
+	arr, sessionID, iter, err := unwrap.ArrayAndSessionIterator(inv.Run(script))
 	if err != nil {
 		if errors.Is(err, unwrap.ErrNoSessionID) {
 			items, err := unwrap.Array(inv.CallAndExpandIterator(nnsHash, "tokens", nnsMaxTokens))
@@ -160,6 +166,10 @@ func dumpCustomZoneHashes(cmd *cobra.Command, nnsHash util.Uint160, zone string,
 			return err
 		}
 	} else {
+		for i := range arr {
+			processItem(arr[i])
+		}
+
 		defer func() {
 			_ = inv.TerminateSession(sessionID)
 		}()