diff --git a/core/blockchain.go b/core/blockchain.go
index 432aee2147..7ac5910cb0 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -175,15 +175,12 @@ type BlockChainConfig struct {
 	Overrides  *ChainOverrides // Optional chain config overrides
 	VmConfig   vm.Config       // Config options for the EVM Interpreter
 
-	// TxLookupLimit specifies the maximum number of blocks from head whose tx
-	// indices are reserved.
+	// TxLookupLimit specifies the maximum number of blocks from head for which
+	// transaction hashes will be indexed.
 	//
-	// If the value is zero, then the transaction indexes of the entire chain
-	// should be reserved.
-	//
-	// If the value is nil, it means the transaction indexing is disabled.
-	// For instance, the chain is opened in read-only mode.
-	TxLookupLimit *uint64
+	// If the value is zero, all transactions of the entire chain will be indexed.
+	// If the value is -1, indexing is disabled. This is the default setting.
+	TxLookupLimit int64
 }
 
 // DefaultConfig returns the default config.
@@ -197,6 +194,9 @@ func DefaultConfig() *BlockChainConfig {
 		SnapshotLimit:    256,
 		SnapshotWait:     true,
 		ChainHistoryMode: history.KeepAll,
+		// Transaction indexing is disabled by default.
+		// This is appropriate for most unit tests.
+		TxLookupLimit: -1,
 	}
 }
 
@@ -501,8 +501,8 @@ func NewBlockChain(db ethdb.Database, genesis *Genesis, engine consensus.Engine,
 	}
 
 	// Start tx indexer if it's enabled.
-	if bc.cfg.TxLookupLimit != nil {
-		bc.txIndexer = newTxIndexer(*bc.cfg.TxLookupLimit, bc)
+	if bc.cfg.TxLookupLimit >= 0 {
+		bc.txIndexer = newTxIndexer(uint64(bc.cfg.TxLookupLimit), bc)
 	}
 	return bc, nil
 }
diff --git a/eth/backend.go b/eth/backend.go
index cd45ba4ed7..0852661676 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -20,6 +20,7 @@ package eth
 import (
 	"encoding/json"
 	"fmt"
+	"math"
 	"math/big"
 	"runtime"
 	"sync"
@@ -205,10 +206,11 @@ func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 			StateHistory:     config.StateHistory,
 			StateScheme:      scheme,
 			ChainHistoryMode: config.HistoryMode,
+			TxLookupLimit:    int64(min(config.TransactionHistory, math.MaxInt64)),
 			VmConfig:         vmConfig,
-			TxLookupLimit:    &config.TransactionHistory,
 		}
 	)
+
 	if config.VMTrace != "" {
 		traceConfig := json.RawMessage("{}")
 		if config.VMTraceJsonConfig != "" {
diff --git a/eth/filters/filter_test.go b/eth/filters/filter_test.go
index a80cd4260f..850d77034d 100644
--- a/eth/filters/filter_test.go
+++ b/eth/filters/filter_test.go
@@ -276,9 +276,8 @@ func testFilters(t *testing.T, history uint64, noHistory bool) {
 			gen.AddTx(tx)
 		}
 	})
-	var l uint64
 	options := core.DefaultConfig().WithStateScheme(rawdb.HashScheme)
-	options.TxLookupLimit = &l
+	options.TxLookupLimit = 0 // index all txs
 	bc, err := core.NewBlockChain(db, gspec, ethash.NewFaker(), options)
 	if err != nil {
 		t.Fatal(err)
@@ -436,9 +435,8 @@ func TestRangeLogs(t *testing.T) {
 	}
 	chain, _ := core.GenerateChain(gspec.Config, gspec.ToBlock(), ethash.NewFaker(), db, 1000, func(i int, gen *core.BlockGen) {})
 
-	var l uint64
 	options := core.DefaultConfig().WithStateScheme(rawdb.HashScheme)
-	options.TxLookupLimit = &l
+	options.TxLookupLimit = 0 // index all txs
 	bc, err := core.NewBlockChain(db, gspec, ethash.NewFaker(), options)
 	if err != nil {
 		t.Fatal(err)
diff --git a/internal/ethapi/api_test.go b/internal/ethapi/api_test.go
index 0b6d19e00f..4d1834d757 100644
--- a/internal/ethapi/api_test.go
+++ b/internal/ethapi/api_test.go
@@ -442,19 +442,12 @@ type testBackend struct {
 }
 
 func newTestBackend(t *testing.T, n int, gspec *core.Genesis, engine consensus.Engine, generator func(i int, b *core.BlockGen)) *testBackend {
-	var (
-		txLookupLimit = uint64(0)
-		options       = &core.BlockChainConfig{
-			TrieCleanLimit: 256,
-			TrieDirtyLimit: 256,
-			TrieTimeLimit:  5 * time.Minute,
-			SnapshotLimit:  0,
-			ArchiveMode:    true, // Archive mode
-			TxLookupLimit:  &txLookupLimit,
-		}
-	)
+	options := core.DefaultConfig().WithArchive(true)
+	options.TxLookupLimit = 0 // index all txs
+
 	accman, acc := newTestAccountManager(t)
 	gspec.Alloc[acc.Address] = types.Account{Balance: big.NewInt(params.Ether)}
+
 	// Generate blocks for testing
 	db, blocks, _ := core.GenerateChainWithGenesis(gspec, engine, n, generator)