Drop Soroban metadata from being stored

services/horizon/internal/db2/history/transaction_batch_insert_builder.go

@@ -164,10 +164,33 @@ func transactionToRow(transaction ingest.LedgerTransaction, sequence uint32, enc
 	if err != nil {
 		return TransactionWithoutLedger{}, err
 	}
-	metaBase64, err := encodingBuffer.MarshalBase64(transaction.UnsafeMeta)
+
+	// We intentionally avoid ingestion of transaction metadata for Soroban
+	// transactions after Protocol 20 due to performance concerns:
+	//   - Soroban @ 10/tps adds 30-100% txmeta/ledger
+	//   - Soroban @ 150/tps means Horizon is unable to ingest meta
+	//   - the data is not ergonomic
+	//   - this data is available in Soroban RPC
+	//
+	// https://stellarfoundation.slack.com/archives/C02B04RMK/p1705624375148539
+	//
+	// In order to avoid breakage, we instead just make the meta appear empty.
+	var metaBase64 string
+	if transaction.UnsafeMeta.V == 3 &&
+		transaction.UnsafeMeta.MustV3().SorobanMeta != nil {
+		transaction.UnsafeMeta.V3 = &xdr.TransactionMetaV3{
+			Ext:             xdr.ExtensionPoint{},
+			TxChangesBefore: xdr.LedgerEntryChanges{},
+			Operations:      []xdr.OperationMeta{},
+			TxChangesAfter:  xdr.LedgerEntryChanges{},
+			SorobanMeta:     nil,
+		}
+	}
+	metaBase64, err = encodingBuffer.MarshalBase64(transaction.UnsafeMeta)
 	if err != nil {
 		return TransactionWithoutLedger{}, err
 	}
+
 	feeMetaBase64, err := encodingBuffer.MarshalBase64(transaction.FeeChanges)
 	if err != nil {
 		return TransactionWithoutLedger{}, err

services/horizon/internal/db2/history/transaction_batch_insert_builder_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/guregu/null"
 	"github.com/lib/pq"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/stellar/go/ingest"
 	"github.com/stellar/go/xdr"
@@ -276,3 +277,110 @@ func TestTransactionToMap_Preconditions(t *testing.T) {
 	assert.Equal(t, null.IntFrom(3), row.MinAccountSequenceLedgerGap)
 	assert.Equal(t, pq.StringArray{signerKey.Address()}, row.ExtraSigners)
 }
+
+func TestTransactionsDropSorobanTxMeta(t *testing.T) {
+	truth := true
+	minSeqNum := xdr.SequenceNumber(math.MaxInt64)
+	source := xdr.MuxedAccount{
+		Type:    xdr.CryptoKeyTypeKeyTypeEd25519,
+		Ed25519: &xdr.Uint256{3, 2, 1},
+	}
+	signerKey := xdr.SignerKey{
+		Type:    xdr.SignerKeyTypeSignerKeyTypeEd25519,
+		Ed25519: source.Ed25519,
+	}
+	tx := ingest.LedgerTransaction{
+		Index: 1,
+		Envelope: xdr.TransactionEnvelope{
+			Type: xdr.EnvelopeTypeEnvelopeTypeTx,
+			V1: &xdr.TransactionV1Envelope{
+				Tx: xdr.Transaction{
+					SourceAccount: source,
+					Operations: []xdr.Operation{
+						{
+							SourceAccount: &source,
+							Body: xdr.OperationBody{
+								Type: xdr.OperationTypePayment,
+								PaymentOp: &xdr.PaymentOp{
+									Destination: source,
+									Asset:       xdr.Asset{Type: xdr.AssetTypeAssetTypeNative},
+									Amount:      100,
+								},
+							},
+						},
+					},
+					Cond: xdr.Preconditions{
+						Type: xdr.PreconditionTypePrecondV2,
+						V2: &xdr.PreconditionsV2{
+							// The important bit.
+							TimeBounds: &xdr.TimeBounds{
+								MinTime: 1000,
+								MaxTime: 2000,
+							},
+							LedgerBounds: &xdr.LedgerBounds{
+								MinLedger: 5,
+								MaxLedger: 10,
+							},
+							MinSeqNum:       &minSeqNum,
+							MinSeqAge:       xdr.Duration(math.MaxUint64),
+							MinSeqLedgerGap: xdr.Uint32(3),
+							ExtraSigners:    []xdr.SignerKey{signerKey},
+						},
+					},
+				},
+			},
+		},
+		Result: xdr.TransactionResultPair{
+			TransactionHash: xdr.Hash{1, 2, 3},
+			Result: xdr.TransactionResult{
+				Result: xdr.TransactionResultResult{
+					Code: xdr.TransactionResultCodeTxFeeBumpInnerSuccess,
+					InnerResultPair: &xdr.InnerTransactionResultPair{
+						TransactionHash: xdr.Hash{3, 2, 1},
+						Result: xdr.InnerTransactionResult{
+							Result: xdr.InnerTransactionResultResult{
+								Results: &[]xdr.OperationResult{},
+							},
+						},
+					},
+					Results: &[]xdr.OperationResult{},
+				},
+			},
+		},
+		UnsafeMeta: xdr.TransactionMeta{
+			V:          3,
+			Operations: &[]xdr.OperationMeta{},
+			V3: &xdr.TransactionMetaV3{
+				TxChangesBefore: []xdr.LedgerEntryChange{
+					{
+						Type: xdr.LedgerEntryChangeTypeLedgerEntryUpdated,
+					},
+					{
+						Type: xdr.LedgerEntryChangeTypeLedgerEntryCreated,
+					},
+				},
+				Operations: []xdr.OperationMeta{{}},
+				TxChangesAfter: []xdr.LedgerEntryChange{{
+					Type: xdr.LedgerEntryChangeTypeLedgerEntryRemoved,
+				}},
+				SorobanMeta: &xdr.SorobanTransactionMeta{
+					ReturnValue: xdr.ScVal{Type: xdr.ScValTypeScvBool, B: &truth},
+				},
+			},
+		},
+	}
+
+	encoder := xdr.NewEncodingBuffer()
+	processedTx, err := transactionToRow(tx, 123, encoder)
+	require.NoError(t, err)
+
+	var meta xdr.TransactionMeta
+	err = xdr.SafeUnmarshalBase64(processedTx.TxMeta, &meta)
+	require.NoError(t, err)
+
+	require.NotNil(t, meta.V3)
+	require.Empty(t, meta.V3.Operations)
+	require.Empty(t, meta.V3.TxChangesAfter)
+	require.Empty(t, meta.V3.TxChangesBefore)
+	require.Nil(t, meta.V3.SorobanMeta)
+}