Merge pull request #571 from hermeznetwork/feature/sql-read-write

Diferentiate SQL connections by read write
2026-02-06 19:06:42 +01:00 · 2021-02-24 15:26:43 +01:00
parent 5cdcae47b8 ed9bfdffa9
commit 155e06484b
17 changed files with 259 additions and 191 deletions
--- a/api/api_test.go
+++ b/api/api_test.go
@@ -201,7 +201,7 @@ func TestMain(m *testing.M) {
 		panic(err)
 	}
 	apiConnCon := db.NewAPICnnectionController(1, time.Second)
-	hdb := historydb.NewHistoryDB(database, apiConnCon)
+	hdb := historydb.NewHistoryDB(database, database, apiConnCon)
 	if err != nil {
 		panic(err)
 	}
@@ -216,7 +216,7 @@ func TestMain(m *testing.M) {
 		}
 	}()
 	// L2DB
-	l2DB := l2db.NewL2DB(database, 10, 1000, 0.0, 24*time.Hour, apiConnCon)
+	l2DB := l2db.NewL2DB(database, database, 10, 1000, 0.0, 24*time.Hour, apiConnCon)
 	test.WipeDB(l2DB.DB()) // this will clean HistoryDB and L2DB
 	// Config (smart contract constants)
 	chainID := uint16(0)
@@ -591,10 +591,10 @@ func TestTimeout(t *testing.T) {
 	databaseTO, err := db.InitSQLDB(5432, "localhost", "hermez", pass, "hermez")
 	require.NoError(t, err)
 	apiConnConTO := db.NewAPICnnectionController(1, 100*time.Millisecond)
-	hdbTO := historydb.NewHistoryDB(databaseTO, apiConnConTO)
+	hdbTO := historydb.NewHistoryDB(databaseTO, databaseTO, apiConnConTO)
 	require.NoError(t, err)
 	// L2DB
-	l2DBTO := l2db.NewL2DB(databaseTO, 10, 1000, 1.0, 24*time.Hour, apiConnConTO)
+	l2DBTO := l2db.NewL2DB(databaseTO, databaseTO, 10, 1000, 1.0, 24*time.Hour, apiConnConTO)

 	// API
 	apiGinTO := gin.Default()
--- a/cli/node/cfg.buidler.toml
+++ b/cli/node/cfg.buidler.toml
@@ -20,11 +20,16 @@ Path = "/tmp/iden3-test/hermez/statedb"
 Keep = 256

 [PostgreSQL]
-Port     = 5432
-Host     = "localhost"
-User     = "hermez"
-Password = "yourpasswordhere"
-Name     = "hermez"
+PortWrite     = 5432
+HostWrite     = "localhost"
+UserWrite     = "hermez"
+PasswordWrite = "yourpasswordhere"
+NameWrite     = "hermez"
+# PortRead     = 5432
+# HostRead     = "localhost"
+# UserRead     = "hermez"
+# PasswordRead = "yourpasswordhere"
+# NameRead     = "hermez"

 [Web3]
 URL = "http://localhost:8545"
--- a/cli/node/main.go
+++ b/cli/node/main.go
@@ -17,6 +17,7 @@ import (
 	"github.com/hermeznetwork/hermez-node/node"
 	"github.com/hermeznetwork/tracerr"
 	"github.com/iden3/go-iden3-crypto/babyjub"
+	"github.com/jmoiron/sqlx"
 	"github.com/urfave/cli/v2"
 )

@@ -90,11 +91,11 @@ func cmdWipeSQL(c *cli.Context) error {
 		}
 	}
 	db, err := dbUtils.ConnectSQLDB(
-		cfg.PostgreSQL.Port,
-		cfg.PostgreSQL.Host,
-		cfg.PostgreSQL.User,
-		cfg.PostgreSQL.Password,
-		cfg.PostgreSQL.Name,
+		cfg.PostgreSQL.PortWrite,
+		cfg.PostgreSQL.HostWrite,
+		cfg.PostgreSQL.UserWrite,
+		cfg.PostgreSQL.PasswordWrite,
+		cfg.PostgreSQL.NameWrite,
 	)
 	if err != nil {
 		return tracerr.Wrap(err)
@@ -151,17 +152,36 @@ func cmdDiscard(c *cli.Context) error {
 	blockNum := c.Int64(flagBlock)
 	log.Infof("Discarding all blocks up to block %v...", blockNum)

-	db, err := dbUtils.InitSQLDB(
-		cfg.PostgreSQL.Port,
-		cfg.PostgreSQL.Host,
-		cfg.PostgreSQL.User,
-		cfg.PostgreSQL.Password,
-		cfg.PostgreSQL.Name,
+	dbWrite, err := dbUtils.InitSQLDB(
+		cfg.PostgreSQL.PortWrite,
+		cfg.PostgreSQL.HostWrite,
+		cfg.PostgreSQL.UserWrite,
+		cfg.PostgreSQL.PasswordWrite,
+		cfg.PostgreSQL.NameWrite,
 	)
 	if err != nil {
 		return tracerr.Wrap(fmt.Errorf("dbUtils.InitSQLDB: %w", err))
 	}
-	historyDB := historydb.NewHistoryDB(db, nil)
+	var dbRead *sqlx.DB
+	if cfg.PostgreSQL.HostRead == "" {
+		dbRead = dbWrite
+	} else if cfg.PostgreSQL.HostRead == cfg.PostgreSQL.HostWrite {
+		return tracerr.Wrap(fmt.Errorf(
+			"PostgreSQL.HostRead and PostgreSQL.HostWrite must be different",
+		))
+	} else {
+		dbRead, err = dbUtils.InitSQLDB(
+			cfg.PostgreSQL.PortRead,
+			cfg.PostgreSQL.HostRead,
+			cfg.PostgreSQL.UserRead,
+			cfg.PostgreSQL.PasswordRead,
+			cfg.PostgreSQL.NameRead,
+		)
+		if err != nil {
+			return tracerr.Wrap(fmt.Errorf("dbUtils.InitSQLDB: %w", err))
+		}
+	}
+	historyDB := historydb.NewHistoryDB(dbRead, dbWrite, nil)
 	if err := historyDB.Reorg(blockNum); err != nil {
 		return tracerr.Wrap(fmt.Errorf("historyDB.Reorg: %w", err))
 	}
@@ -170,7 +190,7 @@ func cmdDiscard(c *cli.Context) error {
 		return tracerr.Wrap(fmt.Errorf("historyDB.GetLastBatchNum: %w", err))
 	}
 	l2DB := l2db.NewL2DB(
-		db,
+		dbRead, dbWrite,
 		cfg.Coordinator.L2DB.SafetyPeriod,
 		cfg.Coordinator.L2DB.MaxTxs,
 		cfg.Coordinator.L2DB.MinFeeUSD,
--- a/config/config.go
+++ b/config/config.go
@@ -215,17 +215,30 @@ type Node struct {
 		// Keep is the number of checkpoints to keep
 		Keep int `validate:"required"`
 	} `validate:"required"`
+	// It's possible to use diferentiated SQL connections for read/write.
+	// If the read configuration is not provided, the write one it's going to be used
+	// for both reads and writes
 	PostgreSQL struct {
-		// Port of the PostgreSQL server
-		Port int `validate:"required"`
-		// Host of the PostgreSQL server
-		Host string `validate:"required"`
-		// User of the PostgreSQL server
-		User string `validate:"required"`
-		// Password of the PostgreSQL server
-		Password string `validate:"required"`
-		// Name of the PostgreSQL server database
-		Name string `validate:"required"`
+		// Port of the PostgreSQL write server
+		PortWrite int `validate:"required"`
+		// Host of the PostgreSQL write server
+		HostWrite string `validate:"required"`
+		// User of the PostgreSQL write server
+		UserWrite string `validate:"required"`
+		// Password of the PostgreSQL write server
+		PasswordWrite string `validate:"required"`
+		// Name of the PostgreSQL write server database
+		NameWrite string `validate:"required"`
+		// Port of the PostgreSQL read server
+		PortRead int
+		// Host of the PostgreSQL read server
+		HostRead string
+		// User of the PostgreSQL read server
+		UserRead string
+		// Password of the PostgreSQL read server
+		PasswordRead string
+		// Name of the PostgreSQL read server database
+		NameRead string
 	} `validate:"required"`
 	Web3 struct {
 		// URL is the URL of the web3 ethereum-node RPC server
--- a/coordinator/coordinator_test.go
+++ b/coordinator/coordinator_test.go
@@ -105,8 +105,8 @@ func newTestModules(t *testing.T) modules {
 	db, err := dbUtils.InitSQLDB(5432, "localhost", "hermez", pass, "hermez")
 	require.NoError(t, err)
 	test.WipeDB(db)
-	l2DB := l2db.NewL2DB(db, 10, 100, 0.0, 24*time.Hour, nil)
-	historyDB := historydb.NewHistoryDB(db, nil)
+	l2DB := l2db.NewL2DB(db, db, 10, 100, 0.0, 24*time.Hour, nil)
+	historyDB := historydb.NewHistoryDB(db, db, nil)

 	txSelDBPath, err = ioutil.TempDir("", "tmpTxSelDB")
 	require.NoError(t, err)
--- a/coordinator/purger_test.go
+++ b/coordinator/purger_test.go
@@ -21,7 +21,7 @@ func newL2DB(t *testing.T) *l2db.L2DB {
 	db, err := dbUtils.InitSQLDB(5432, "localhost", "hermez", pass, "hermez")
 	require.NoError(t, err)
 	test.WipeDB(db)
-	return l2db.NewL2DB(db, 10, 100, 0.0, 24*time.Hour, nil)
+	return l2db.NewL2DB(db, db, 10, 100, 0.0, 24*time.Hour, nil)
 }

 func newStateDB(t *testing.T) *statedb.LocalStateDB {
--- a/db/historydb/apiqueries.go
+++ b/db/historydb/apiqueries.go
@@ -34,7 +34,7 @@ func (hdb *HistoryDB) GetBatchAPI(batchNum common.BatchNum) (*BatchAPI, error) {
 	defer hdb.apiConnCon.Release()
 	batch := &BatchAPI{}
 	return batch, tracerr.Wrap(meddler.QueryRow(
-		hdb.db, batch,
+		hdb.dbRead, batch,
 		`SELECT batch.item_id, batch.batch_num, batch.eth_block_num,
 		batch.forger_addr, batch.fees_collected, batch.total_fees_usd, batch.state_root,
 		batch.num_accounts, batch.exit_root, batch.forge_l1_txs_num, batch.slot_num,
@@ -133,10 +133,10 @@ func (hdb *HistoryDB) GetBatchesAPI(
 		queryStr += " DESC "
 	}
 	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query = hdb.db.Rebind(queryStr)
+	query = hdb.dbRead.Rebind(queryStr)
 	// log.Debug(query)
 	batchPtrs := []*BatchAPI{}
-	if err := meddler.QueryAll(hdb.db, &batchPtrs, query, args...); err != nil {
+	if err := meddler.QueryAll(hdb.dbRead, &batchPtrs, query, args...); err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
 	batches := db.SlicePtrsToSlice(batchPtrs).([]BatchAPI)
@@ -156,7 +156,7 @@ func (hdb *HistoryDB) GetBestBidAPI(slotNum *int64) (BidAPI, error) {
 	}
 	defer hdb.apiConnCon.Release()
 	err = meddler.QueryRow(
-		hdb.db, bid, `SELECT bid.*, block.timestamp, coordinator.forger_addr, coordinator.url 
+		hdb.dbRead, bid, `SELECT bid.*, block.timestamp, coordinator.forger_addr, coordinator.url 
 		FROM bid INNER JOIN block ON bid.eth_block_num = block.eth_block_num
 		INNER JOIN (
 			SELECT bidder_addr, MAX(item_id) AS item_id FROM coordinator
@@ -212,9 +212,9 @@ func (hdb *HistoryDB) GetBestBidsAPI(
 	if limit != nil {
 		queryStr += fmt.Sprintf("LIMIT %d;", *limit)
 	}
-	query = hdb.db.Rebind(queryStr)
+	query = hdb.dbRead.Rebind(queryStr)
 	bidPtrs := []*BidAPI{}
-	if err := meddler.QueryAll(hdb.db, &bidPtrs, query, args...); err != nil {
+	if err := meddler.QueryAll(hdb.dbRead, &bidPtrs, query, args...); err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
 	// log.Debug(query)
@@ -296,9 +296,9 @@ func (hdb *HistoryDB) GetBidsAPI(
 	if err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
-	query = hdb.db.Rebind(query)
+	query = hdb.dbRead.Rebind(query)
 	bids := []*BidAPI{}
-	if err := meddler.QueryAll(hdb.db, &bids, query, argsQ...); err != nil {
+	if err := meddler.QueryAll(hdb.dbRead, &bids, query, argsQ...); err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
 	if len(bids) == 0 {
@@ -384,9 +384,9 @@ func (hdb *HistoryDB) GetTokensAPI(
 	if err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
-	query = hdb.db.Rebind(query)
+	query = hdb.dbRead.Rebind(query)
 	tokens := []*TokenWithUSD{}
-	if err := meddler.QueryAll(hdb.db, &tokens, query, argsQ...); err != nil {
+	if err := meddler.QueryAll(hdb.dbRead, &tokens, query, argsQ...); err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
 	if len(tokens) == 0 {
@@ -408,7 +408,7 @@ func (hdb *HistoryDB) GetTxAPI(txID common.TxID) (*TxAPI, error) {
 	defer hdb.apiConnCon.Release()
 	tx := &TxAPI{}
 	err = meddler.QueryRow(
-		hdb.db, tx, `SELECT tx.item_id, tx.is_l1, tx.id, tx.type, tx.position, 
+		hdb.dbRead, tx, `SELECT tx.item_id, tx.is_l1, tx.id, tx.type, tx.position, 
 		hez_idx(tx.effective_from_idx, token.symbol) AS from_idx, tx.from_eth_addr, tx.from_bjj,
 		hez_idx(tx.to_idx, token.symbol) AS to_idx, tx.to_eth_addr, tx.to_bjj,
 		tx.amount, tx.amount_success, tx.token_id, tx.amount_usd, 
@@ -541,10 +541,10 @@ func (hdb *HistoryDB) GetTxsAPI(
 		queryStr += " DESC "
 	}
 	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query = hdb.db.Rebind(queryStr)
+	query = hdb.dbRead.Rebind(queryStr)
 	// log.Debug(query)
 	txsPtrs := []*TxAPI{}
-	if err := meddler.QueryAll(hdb.db, &txsPtrs, query, args...); err != nil {
+	if err := meddler.QueryAll(hdb.dbRead, &txsPtrs, query, args...); err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
 	txs := db.SlicePtrsToSlice(txsPtrs).([]TxAPI)
@@ -564,7 +564,7 @@ func (hdb *HistoryDB) GetExitAPI(batchNum *uint, idx *common.Idx) (*ExitAPI, err
 	defer hdb.apiConnCon.Release()
 	exit := &ExitAPI{}
 	err = meddler.QueryRow(
-		hdb.db, exit, `SELECT exit_tree.item_id, exit_tree.batch_num,
+		hdb.dbRead, exit, `SELECT exit_tree.item_id, exit_tree.batch_num,
 		hez_idx(exit_tree.account_idx, token.symbol) AS account_idx,
 		account.bjj, account.eth_addr,
 		exit_tree.merkle_proof, exit_tree.balance, exit_tree.instant_withdrawn,
@@ -685,10 +685,10 @@ func (hdb *HistoryDB) GetExitsAPI(
 		queryStr += " DESC "
 	}
 	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query = hdb.db.Rebind(queryStr)
+	query = hdb.dbRead.Rebind(queryStr)
 	// log.Debug(query)
 	exits := []*ExitAPI{}
-	if err := meddler.QueryAll(hdb.db, &exits, query, args...); err != nil {
+	if err := meddler.QueryAll(hdb.dbRead, &exits, query, args...); err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
 	if len(exits) == 0 {
@@ -707,7 +707,7 @@ func (hdb *HistoryDB) GetBucketUpdatesAPI() ([]BucketUpdateAPI, error) {
 	defer hdb.apiConnCon.Release()
 	var bucketUpdates []*BucketUpdateAPI
 	err = meddler.QueryAll(
-		hdb.db, &bucketUpdates,
+		hdb.dbRead, &bucketUpdates,
 		`SELECT num_bucket, withdrawals FROM bucket_update 
 		WHERE item_id in(SELECT max(item_id) FROM bucket_update 
 		group by num_bucket) 
@@ -772,10 +772,10 @@ func (hdb *HistoryDB) GetCoordinatorsAPI(
 		queryStr += " DESC "
 	}
 	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query = hdb.db.Rebind(queryStr)
+	query = hdb.dbRead.Rebind(queryStr)

 	coordinators := []*CoordinatorAPI{}
-	if err := meddler.QueryAll(hdb.db, &coordinators, query, args...); err != nil {
+	if err := meddler.QueryAll(hdb.dbRead, &coordinators, query, args...); err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
 	if len(coordinators) == 0 {
@@ -795,7 +795,7 @@ func (hdb *HistoryDB) GetAuctionVarsAPI() (*common.AuctionVariables, error) {
 	defer hdb.apiConnCon.Release()
 	auctionVars := &common.AuctionVariables{}
 	err = meddler.QueryRow(
-		hdb.db, auctionVars, `SELECT * FROM auction_vars;`,
+		hdb.dbRead, auctionVars, `SELECT * FROM auction_vars;`,
 	)
 	return auctionVars, tracerr.Wrap(err)
 }
@@ -816,7 +816,7 @@ func (hdb *HistoryDB) GetAuctionVarsUntilSetSlotNumAPI(slotNum int64, maxItems i
 		ORDER BY default_slot_set_bid_slot_num DESC
 		LIMIT $2;
 	`
-	err = meddler.QueryAll(hdb.db, &auctionVars, query, slotNum, maxItems)
+	err = meddler.QueryAll(hdb.dbRead, &auctionVars, query, slotNum, maxItems)
 	if err != nil {
 		return nil, tracerr.Wrap(err)
 	}
@@ -832,7 +832,7 @@ func (hdb *HistoryDB) GetAccountAPI(idx common.Idx) (*AccountAPI, error) {
 	}
 	defer hdb.apiConnCon.Release()
 	account := &AccountAPI{}
-	err = meddler.QueryRow(hdb.db, account, `SELECT account.item_id, hez_idx(account.idx, 
+	err = meddler.QueryRow(hdb.dbRead, account, `SELECT account.item_id, hez_idx(account.idx, 
 		token.symbol) as idx, account.batch_num, account.bjj, account.eth_addr,
 		token.token_id, token.item_id AS token_item_id, token.eth_block_num AS token_block,
 		token.eth_addr as token_eth_addr, token.name, token.symbol, token.decimals, token.usd,
@@ -927,10 +927,10 @@ func (hdb *HistoryDB) GetAccountsAPI(
 	if err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
-	query = hdb.db.Rebind(query)
+	query = hdb.dbRead.Rebind(query)

 	accounts := []*AccountAPI{}
-	if err := meddler.QueryAll(hdb.db, &accounts, query, argsQ...); err != nil {
+	if err := meddler.QueryAll(hdb.dbRead, &accounts, query, argsQ...); err != nil {
 		return nil, 0, tracerr.Wrap(err)
 	}
 	if len(accounts) == 0 {
@@ -952,7 +952,7 @@ func (hdb *HistoryDB) GetMetricsAPI(lastBatchNum common.BatchNum) (*Metrics, err
 	metricsTotals := &MetricsTotals{}
 	metrics := &Metrics{}
 	err = meddler.QueryRow(
-		hdb.db, metricsTotals, `SELECT COUNT(tx.*) as total_txs,
+		hdb.dbRead, metricsTotals, `SELECT COUNT(tx.*) as total_txs,
 		COALESCE (MIN(tx.batch_num), 0) as batch_num, COALESCE (MIN(block.timestamp), 
 		NOW()) AS min_timestamp, COALESCE (MAX(block.timestamp), NOW()) AS max_timestamp
 		FROM tx INNER JOIN block ON tx.eth_block_num = block.eth_block_num
@@ -977,7 +977,7 @@ func (hdb *HistoryDB) GetMetricsAPI(lastBatchNum common.BatchNum) (*Metrics, err
 	}

 	err = meddler.QueryRow(
-		hdb.db, metricsTotals, `SELECT COUNT(*) AS total_batches, 
+		hdb.dbRead, metricsTotals, `SELECT COUNT(*) AS total_batches, 
 		COALESCE (SUM(total_fees_usd), 0) AS total_fees FROM batch 
 		WHERE batch_num > $1;`, metricsTotals.FirstBatchNum)
 	if err != nil {
@@ -994,7 +994,7 @@ func (hdb *HistoryDB) GetMetricsAPI(lastBatchNum common.BatchNum) (*Metrics, err
 		metrics.AvgTransactionFee = 0
 	}
 	err = meddler.QueryRow(
-		hdb.db, metrics,
+		hdb.dbRead, metrics,
 		`SELECT COUNT(*) AS total_bjjs, COUNT(DISTINCT(bjj)) AS total_accounts FROM account;`)
 	if err != nil {
 		return nil, tracerr.Wrap(err)
@@ -1013,7 +1013,7 @@ func (hdb *HistoryDB) GetAvgTxFeeAPI() (float64, error) {
 	defer hdb.apiConnCon.Release()
 	metricsTotals := &MetricsTotals{}
 	err = meddler.QueryRow(
-		hdb.db, metricsTotals, `SELECT COUNT(tx.*) as total_txs, 
+		hdb.dbRead, metricsTotals, `SELECT COUNT(tx.*) as total_txs, 
 		COALESCE (MIN(tx.batch_num), 0) as batch_num 
 		FROM tx INNER JOIN block ON tx.eth_block_num = block.eth_block_num
 		WHERE block.timestamp >= NOW() - INTERVAL '1 HOURS';`)
@@ -1021,7 +1021,7 @@ func (hdb *HistoryDB) GetAvgTxFeeAPI() (float64, error) {
 		return 0, tracerr.Wrap(err)
 	}
 	err = meddler.QueryRow(
-		hdb.db, metricsTotals, `SELECT COUNT(*) AS total_batches, 
+		hdb.dbRead, metricsTotals, `SELECT COUNT(*) AS total_batches, 
 		COALESCE (SUM(total_fees_usd), 0) AS total_fees FROM batch 
 		WHERE batch_num > $1;`, metricsTotals.FirstBatchNum)
 	if err != nil {
@@ -1048,7 +1048,7 @@ func (hdb *HistoryDB) GetCommonAccountAPI(idx common.Idx) (*common.Account, erro
 	defer hdb.apiConnCon.Release()
 	account := &common.Account{}
 	err = meddler.QueryRow(
-		hdb.db, account, `SELECT * FROM account WHERE idx = $1;`, idx,
+		hdb.dbRead, account, `SELECT * FROM account WHERE idx = $1;`, idx,
 	)
 	return account, tracerr.Wrap(err)
 }
--- a/db/historydb/historydb.go
+++ b/db/historydb/historydb.go
@@ -27,30 +27,35 @@ const (

 // HistoryDB persist the historic of the rollup
 type HistoryDB struct {
-	db         *sqlx.DB
+	dbRead     *sqlx.DB
+	dbWrite    *sqlx.DB
 	apiConnCon *db.APIConnectionController
 }

 // NewHistoryDB initialize the DB
-func NewHistoryDB(db *sqlx.DB, apiConnCon *db.APIConnectionController) *HistoryDB {
-	return &HistoryDB{db: db, apiConnCon: apiConnCon}
+func NewHistoryDB(dbRead, dbWrite *sqlx.DB, apiConnCon *db.APIConnectionController) *HistoryDB {
+	return &HistoryDB{
+		dbRead:     dbRead,
+		dbWrite:    dbWrite,
+		apiConnCon: apiConnCon,
+	}
 }

 // DB returns a pointer to the L2DB.db. This method should be used only for
 // internal testing purposes.
 func (hdb *HistoryDB) DB() *sqlx.DB {
-	return hdb.db
+	return hdb.dbWrite
 }

 // AddBlock insert a block into the DB
-func (hdb *HistoryDB) AddBlock(block *common.Block) error { return hdb.addBlock(hdb.db, block) }
+func (hdb *HistoryDB) AddBlock(block *common.Block) error { return hdb.addBlock(hdb.dbWrite, block) }
 func (hdb *HistoryDB) addBlock(d meddler.DB, block *common.Block) error {
 	return tracerr.Wrap(meddler.Insert(d, "block", block))
 }

 // AddBlocks inserts blocks into the DB
 func (hdb *HistoryDB) AddBlocks(blocks []common.Block) error {
-	return tracerr.Wrap(hdb.addBlocks(hdb.db, blocks))
+	return tracerr.Wrap(hdb.addBlocks(hdb.dbWrite, blocks))
 }

 func (hdb *HistoryDB) addBlocks(d meddler.DB, blocks []common.Block) error {
@@ -69,7 +74,7 @@ func (hdb *HistoryDB) addBlocks(d meddler.DB, blocks []common.Block) error {
 func (hdb *HistoryDB) GetBlock(blockNum int64) (*common.Block, error) {
 	block := &common.Block{}
 	err := meddler.QueryRow(
-		hdb.db, block,
+		hdb.dbRead, block,
 		"SELECT * FROM block WHERE eth_block_num = $1;", blockNum,
 	)
 	return block, tracerr.Wrap(err)
@@ -79,7 +84,7 @@ func (hdb *HistoryDB) GetBlock(blockNum int64) (*common.Block, error) {
 func (hdb *HistoryDB) GetAllBlocks() ([]common.Block, error) {
 	var blocks []*common.Block
 	err := meddler.QueryAll(
-		hdb.db, &blocks,
+		hdb.dbRead, &blocks,
 		"SELECT * FROM block ORDER BY eth_block_num;",
 	)
 	return db.SlicePtrsToSlice(blocks).([]common.Block), tracerr.Wrap(err)
@@ -89,7 +94,7 @@ func (hdb *HistoryDB) GetAllBlocks() ([]common.Block, error) {
 func (hdb *HistoryDB) getBlocks(from, to int64) ([]common.Block, error) {
 	var blocks []*common.Block
 	err := meddler.QueryAll(
-		hdb.db, &blocks,
+		hdb.dbRead, &blocks,
 		"SELECT * FROM block WHERE $1 <= eth_block_num AND eth_block_num < $2 ORDER BY eth_block_num;",
 		from, to,
 	)
@@ -100,13 +105,13 @@ func (hdb *HistoryDB) getBlocks(from, to int64) ([]common.Block, error) {
 func (hdb *HistoryDB) GetLastBlock() (*common.Block, error) {
 	block := &common.Block{}
 	err := meddler.QueryRow(
-		hdb.db, block, "SELECT * FROM block ORDER BY eth_block_num DESC LIMIT 1;",
+		hdb.dbRead, block, "SELECT * FROM block ORDER BY eth_block_num DESC LIMIT 1;",
 	)
 	return block, tracerr.Wrap(err)
 }

 // AddBatch insert a Batch into the DB
-func (hdb *HistoryDB) AddBatch(batch *common.Batch) error { return hdb.addBatch(hdb.db, batch) }
+func (hdb *HistoryDB) AddBatch(batch *common.Batch) error { return hdb.addBatch(hdb.dbWrite, batch) }
 func (hdb *HistoryDB) addBatch(d meddler.DB, batch *common.Batch) error {
 	// Calculate total collected fees in USD
 	// Get IDs of collected tokens for fees
@@ -129,9 +134,9 @@ func (hdb *HistoryDB) addBatch(d meddler.DB, batch *common.Batch) error {
 		if err != nil {
 			return tracerr.Wrap(err)
 		}
-		query = hdb.db.Rebind(query)
+		query = hdb.dbWrite.Rebind(query)
 		if err := meddler.QueryAll(
-			hdb.db, &tokenPrices, query, args...,
+			hdb.dbWrite, &tokenPrices, query, args...,
 		); err != nil {
 			return tracerr.Wrap(err)
 		}
@@ -153,7 +158,7 @@ func (hdb *HistoryDB) addBatch(d meddler.DB, batch *common.Batch) error {

 // AddBatches insert Bids into the DB
 func (hdb *HistoryDB) AddBatches(batches []common.Batch) error {
-	return tracerr.Wrap(hdb.addBatches(hdb.db, batches))
+	return tracerr.Wrap(hdb.addBatches(hdb.dbWrite, batches))
 }
 func (hdb *HistoryDB) addBatches(d meddler.DB, batches []common.Batch) error {
 	for i := 0; i < len(batches); i++ {
@@ -168,7 +173,7 @@ func (hdb *HistoryDB) addBatches(d meddler.DB, batches []common.Batch) error {
 func (hdb *HistoryDB) GetBatch(batchNum common.BatchNum) (*common.Batch, error) {
 	var batch common.Batch
 	err := meddler.QueryRow(
-		hdb.db, &batch, `SELECT batch.batch_num, batch.eth_block_num, batch.forger_addr,
+		hdb.dbRead, &batch, `SELECT batch.batch_num, batch.eth_block_num, batch.forger_addr,
 		batch.fees_collected, batch.fee_idxs_coordinator, batch.state_root,
 		batch.num_accounts, batch.last_idx, batch.exit_root, batch.forge_l1_txs_num,
 		batch.slot_num, batch.total_fees_usd FROM batch WHERE batch_num = $1;`,
@@ -181,7 +186,7 @@ func (hdb *HistoryDB) GetBatch(batchNum common.BatchNum) (*common.Batch, error)
 func (hdb *HistoryDB) GetAllBatches() ([]common.Batch, error) {
 	var batches []*common.Batch
 	err := meddler.QueryAll(
-		hdb.db, &batches,
+		hdb.dbRead, &batches,
 		`SELECT batch.batch_num, batch.eth_block_num, batch.forger_addr, batch.fees_collected,
 		 batch.fee_idxs_coordinator, batch.state_root, batch.num_accounts, batch.last_idx, batch.exit_root,
 		 batch.forge_l1_txs_num, batch.slot_num, batch.total_fees_usd FROM batch
@@ -194,7 +199,7 @@ func (hdb *HistoryDB) GetAllBatches() ([]common.Batch, error) {
 func (hdb *HistoryDB) GetBatches(from, to common.BatchNum) ([]common.Batch, error) {
 	var batches []*common.Batch
 	err := meddler.QueryAll(
-		hdb.db, &batches,
+		hdb.dbRead, &batches,
 		`SELECT batch_num, eth_block_num, forger_addr, fees_collected, fee_idxs_coordinator, 
 		state_root, num_accounts, last_idx, exit_root, forge_l1_txs_num, slot_num, total_fees_usd 
 		FROM batch WHERE $1 <= batch_num AND batch_num < $2 ORDER BY batch_num;`,
@@ -206,7 +211,7 @@ func (hdb *HistoryDB) GetBatches(from, to common.BatchNum) ([]common.Batch, erro
 // GetFirstBatchBlockNumBySlot returns the ethereum block number of the first
 // batch within a slot
 func (hdb *HistoryDB) GetFirstBatchBlockNumBySlot(slotNum int64) (int64, error) {
-	row := hdb.db.QueryRow(
+	row := hdb.dbRead.QueryRow(
 		`SELECT eth_block_num FROM batch
 		WHERE slot_num = $1 ORDER BY batch_num ASC LIMIT 1;`, slotNum,
 	)
@@ -216,7 +221,7 @@ func (hdb *HistoryDB) GetFirstBatchBlockNumBySlot(slotNum int64) (int64, error)

 // GetLastBatchNum returns the BatchNum of the latest forged batch
 func (hdb *HistoryDB) GetLastBatchNum() (common.BatchNum, error) {
-	row := hdb.db.QueryRow("SELECT batch_num FROM batch ORDER BY batch_num DESC LIMIT 1;")
+	row := hdb.dbRead.QueryRow("SELECT batch_num FROM batch ORDER BY batch_num DESC LIMIT 1;")
 	var batchNum common.BatchNum
 	return batchNum, tracerr.Wrap(row.Scan(&batchNum))
 }
@@ -225,7 +230,7 @@ func (hdb *HistoryDB) GetLastBatchNum() (common.BatchNum, error) {
 func (hdb *HistoryDB) GetLastBatch() (*common.Batch, error) {
 	var batch common.Batch
 	err := meddler.QueryRow(
-		hdb.db, &batch, `SELECT batch.batch_num, batch.eth_block_num, batch.forger_addr,
+		hdb.dbRead, &batch, `SELECT batch.batch_num, batch.eth_block_num, batch.forger_addr,
 		batch.fees_collected, batch.fee_idxs_coordinator, batch.state_root,
 		batch.num_accounts, batch.last_idx, batch.exit_root, batch.forge_l1_txs_num,
 		batch.slot_num, batch.total_fees_usd FROM batch ORDER BY batch_num DESC LIMIT 1;`,
@@ -235,7 +240,7 @@ func (hdb *HistoryDB) GetLastBatch() (*common.Batch, error) {

 // GetLastL1BatchBlockNum returns the blockNum of the latest forged l1Batch
 func (hdb *HistoryDB) GetLastL1BatchBlockNum() (int64, error) {
-	row := hdb.db.QueryRow(`SELECT eth_block_num FROM batch
+	row := hdb.dbRead.QueryRow(`SELECT eth_block_num FROM batch
 		WHERE forge_l1_txs_num IS NOT NULL
 		ORDER BY batch_num DESC LIMIT 1;`)
 	var blockNum int64
@@ -245,7 +250,7 @@ func (hdb *HistoryDB) GetLastL1BatchBlockNum() (int64, error) {
 // GetLastL1TxsNum returns the greatest ForgeL1TxsNum in the DB from forged
 // batches.  If there's no batch in the DB (nil, nil) is returned.
 func (hdb *HistoryDB) GetLastL1TxsNum() (*int64, error) {
-	row := hdb.db.QueryRow("SELECT MAX(forge_l1_txs_num) FROM batch;")
+	row := hdb.dbRead.QueryRow("SELECT MAX(forge_l1_txs_num) FROM batch;")
 	lastL1TxsNum := new(int64)
 	return lastL1TxsNum, tracerr.Wrap(row.Scan(&lastL1TxsNum))
 }
@@ -256,15 +261,15 @@ func (hdb *HistoryDB) GetLastL1TxsNum() (*int64, error) {
 func (hdb *HistoryDB) Reorg(lastValidBlock int64) error {
 	var err error
 	if lastValidBlock < 0 {
-		_, err = hdb.db.Exec("DELETE FROM block;")
+		_, err = hdb.dbWrite.Exec("DELETE FROM block;")
 	} else {
-		_, err = hdb.db.Exec("DELETE FROM block WHERE eth_block_num > $1;", lastValidBlock)
+		_, err = hdb.dbWrite.Exec("DELETE FROM block WHERE eth_block_num > $1;", lastValidBlock)
 	}
 	return tracerr.Wrap(err)
 }

 // AddBids insert Bids into the DB
-func (hdb *HistoryDB) AddBids(bids []common.Bid) error { return hdb.addBids(hdb.db, bids) }
+func (hdb *HistoryDB) AddBids(bids []common.Bid) error { return hdb.addBids(hdb.dbWrite, bids) }
 func (hdb *HistoryDB) addBids(d meddler.DB, bids []common.Bid) error {
 	if len(bids) == 0 {
 		return nil
@@ -281,7 +286,7 @@ func (hdb *HistoryDB) addBids(d meddler.DB, bids []common.Bid) error {
 func (hdb *HistoryDB) GetAllBids() ([]common.Bid, error) {
 	var bids []*common.Bid
 	err := meddler.QueryAll(
-		hdb.db, &bids,
+		hdb.dbRead, &bids,
 		`SELECT bid.slot_num, bid.bid_value, bid.eth_block_num, bid.bidder_addr FROM bid
 		ORDER BY item_id;`,
 	)
@@ -292,7 +297,7 @@ func (hdb *HistoryDB) GetAllBids() ([]common.Bid, error) {
 func (hdb *HistoryDB) GetBestBidCoordinator(slotNum int64) (*common.BidCoordinator, error) {
 	bidCoord := &common.BidCoordinator{}
 	err := meddler.QueryRow(
-		hdb.db, bidCoord,
+		hdb.dbRead, bidCoord,
 		`SELECT (
 			SELECT default_slot_set_bid
 			FROM auction_vars
@@ -315,7 +320,7 @@ func (hdb *HistoryDB) GetBestBidCoordinator(slotNum int64) (*common.BidCoordinat

 // AddCoordinators insert Coordinators into the DB
 func (hdb *HistoryDB) AddCoordinators(coordinators []common.Coordinator) error {
-	return tracerr.Wrap(hdb.addCoordinators(hdb.db, coordinators))
+	return tracerr.Wrap(hdb.addCoordinators(hdb.dbWrite, coordinators))
 }
 func (hdb *HistoryDB) addCoordinators(d meddler.DB, coordinators []common.Coordinator) error {
 	if len(coordinators) == 0 {
@@ -330,7 +335,7 @@ func (hdb *HistoryDB) addCoordinators(d meddler.DB, coordinators []common.Coordi

 // AddExitTree insert Exit tree into the DB
 func (hdb *HistoryDB) AddExitTree(exitTree []common.ExitInfo) error {
-	return tracerr.Wrap(hdb.addExitTree(hdb.db, exitTree))
+	return tracerr.Wrap(hdb.addExitTree(hdb.dbWrite, exitTree))
 }
 func (hdb *HistoryDB) addExitTree(d meddler.DB, exitTree []common.ExitInfo) error {
 	if len(exitTree) == 0 {
@@ -418,11 +423,13 @@ func (hdb *HistoryDB) updateExitTree(d sqlx.Ext, blockNum int64,

 // AddToken insert a token into the DB
 func (hdb *HistoryDB) AddToken(token *common.Token) error {
-	return tracerr.Wrap(meddler.Insert(hdb.db, "token", token))
+	return tracerr.Wrap(meddler.Insert(hdb.dbWrite, "token", token))
 }

 // AddTokens insert tokens into the DB
-func (hdb *HistoryDB) AddTokens(tokens []common.Token) error { return hdb.addTokens(hdb.db, tokens) }
+func (hdb *HistoryDB) AddTokens(tokens []common.Token) error {
+	return hdb.addTokens(hdb.dbWrite, tokens)
+}
 func (hdb *HistoryDB) addTokens(d meddler.DB, tokens []common.Token) error {
 	if len(tokens) == 0 {
 		return nil
@@ -453,7 +460,7 @@ func (hdb *HistoryDB) UpdateTokenValue(tokenSymbol string, value float64) error
 	// Sanitize symbol
 	tokenSymbol = strings.ToValidUTF8(tokenSymbol, " ")

-	_, err := hdb.db.Exec(
+	_, err := hdb.dbWrite.Exec(
 		"UPDATE token SET usd = $1 WHERE symbol = $2;",
 		value, tokenSymbol,
 	)
@@ -464,7 +471,7 @@ func (hdb *HistoryDB) UpdateTokenValue(tokenSymbol string, value float64) error
 func (hdb *HistoryDB) GetToken(tokenID common.TokenID) (*TokenWithUSD, error) {
 	token := &TokenWithUSD{}
 	err := meddler.QueryRow(
-		hdb.db, token, `SELECT * FROM token WHERE token_id = $1;`, tokenID,
+		hdb.dbRead, token, `SELECT * FROM token WHERE token_id = $1;`, tokenID,
 	)
 	return token, tracerr.Wrap(err)
 }
@@ -473,7 +480,7 @@ func (hdb *HistoryDB) GetToken(tokenID common.TokenID) (*TokenWithUSD, error) {
 func (hdb *HistoryDB) GetAllTokens() ([]TokenWithUSD, error) {
 	var tokens []*TokenWithUSD
 	err := meddler.QueryAll(
-		hdb.db, &tokens,
+		hdb.dbRead, &tokens,
 		"SELECT * FROM token ORDER BY token_id;",
 	)
 	return db.SlicePtrsToSlice(tokens).([]TokenWithUSD), tracerr.Wrap(err)
@@ -482,7 +489,7 @@ func (hdb *HistoryDB) GetAllTokens() ([]TokenWithUSD, error) {
 // GetTokenSymbols returns all the token symbols from the DB
 func (hdb *HistoryDB) GetTokenSymbols() ([]string, error) {
 	var tokenSymbols []string
-	rows, err := hdb.db.Query("SELECT symbol FROM token;")
+	rows, err := hdb.dbRead.Query("SELECT symbol FROM token;")
 	if err != nil {
 		return nil, tracerr.Wrap(err)
 	}
@@ -500,7 +507,7 @@ func (hdb *HistoryDB) GetTokenSymbols() ([]string, error) {

 // AddAccounts insert accounts into the DB
 func (hdb *HistoryDB) AddAccounts(accounts []common.Account) error {
-	return tracerr.Wrap(hdb.addAccounts(hdb.db, accounts))
+	return tracerr.Wrap(hdb.addAccounts(hdb.dbWrite, accounts))
 }
 func (hdb *HistoryDB) addAccounts(d meddler.DB, accounts []common.Account) error {
 	if len(accounts) == 0 {
@@ -523,7 +530,7 @@ func (hdb *HistoryDB) addAccounts(d meddler.DB, accounts []common.Account) error
 func (hdb *HistoryDB) GetAllAccounts() ([]common.Account, error) {
 	var accs []*common.Account
 	err := meddler.QueryAll(
-		hdb.db, &accs,
+		hdb.dbRead, &accs,
 		"SELECT idx, token_id, batch_num, bjj, eth_addr FROM account ORDER BY idx;",
 	)
 	return db.SlicePtrsToSlice(accs).([]common.Account), tracerr.Wrap(err)
@@ -531,7 +538,7 @@ func (hdb *HistoryDB) GetAllAccounts() ([]common.Account, error) {

 // AddAccountUpdates inserts accUpdates into the DB
 func (hdb *HistoryDB) AddAccountUpdates(accUpdates []common.AccountUpdate) error {
-	return tracerr.Wrap(hdb.addAccountUpdates(hdb.db, accUpdates))
+	return tracerr.Wrap(hdb.addAccountUpdates(hdb.dbWrite, accUpdates))
 }
 func (hdb *HistoryDB) addAccountUpdates(d meddler.DB, accUpdates []common.AccountUpdate) error {
 	if len(accUpdates) == 0 {
@@ -554,7 +561,7 @@ func (hdb *HistoryDB) addAccountUpdates(d meddler.DB, accUpdates []common.Accoun
 func (hdb *HistoryDB) GetAllAccountUpdates() ([]common.AccountUpdate, error) {
 	var accUpdates []*common.AccountUpdate
 	err := meddler.QueryAll(
-		hdb.db, &accUpdates,
+		hdb.dbRead, &accUpdates,
 		"SELECT eth_block_num, batch_num, idx, nonce, balance FROM account_update ORDER BY idx;",
 	)
 	return db.SlicePtrsToSlice(accUpdates).([]common.AccountUpdate), tracerr.Wrap(err)
@@ -565,7 +572,7 @@ func (hdb *HistoryDB) GetAllAccountUpdates() ([]common.AccountUpdate, error) {
 // BatchNum should be null, and the value will be setted by a trigger when a batch forges the tx.
 // EffectiveAmount and EffectiveDepositAmount are seted with default values by the DB.
 func (hdb *HistoryDB) AddL1Txs(l1txs []common.L1Tx) error {
-	return tracerr.Wrap(hdb.addL1Txs(hdb.db, l1txs))
+	return tracerr.Wrap(hdb.addL1Txs(hdb.dbWrite, l1txs))
 }

 // addL1Txs inserts L1 txs to the DB. USD and DepositAmountUSD will be set automatically before storing the tx.
@@ -619,7 +626,7 @@ func (hdb *HistoryDB) addL1Txs(d meddler.DB, l1txs []common.L1Tx) error {

 // AddL2Txs inserts L2 txs to the DB. TokenID, USD and FeeUSD will be set automatically before storing the tx.
 func (hdb *HistoryDB) AddL2Txs(l2txs []common.L2Tx) error {
-	return tracerr.Wrap(hdb.addL2Txs(hdb.db, l2txs))
+	return tracerr.Wrap(hdb.addL2Txs(hdb.dbWrite, l2txs))
 }

 // addL2Txs inserts L2 txs to the DB. TokenID, USD and FeeUSD will be set automatically before storing the tx.
@@ -686,7 +693,7 @@ func (hdb *HistoryDB) addTxs(d meddler.DB, txs []txWrite) error {
 func (hdb *HistoryDB) GetAllExits() ([]common.ExitInfo, error) {
 	var exits []*common.ExitInfo
 	err := meddler.QueryAll(
-		hdb.db, &exits,
+		hdb.dbRead, &exits,
 		`SELECT exit_tree.batch_num, exit_tree.account_idx, exit_tree.merkle_proof,
 		exit_tree.balance, exit_tree.instant_withdrawn, exit_tree.delayed_withdraw_request,
 		exit_tree.delayed_withdrawn FROM exit_tree ORDER BY item_id;`,
@@ -698,7 +705,7 @@ func (hdb *HistoryDB) GetAllExits() ([]common.ExitInfo, error) {
 func (hdb *HistoryDB) GetAllL1UserTxs() ([]common.L1Tx, error) {
 	var txs []*common.L1Tx
 	err := meddler.QueryAll(
-		hdb.db, &txs, // Note that '\x' gets parsed as a big.Int with value = 0
+		hdb.dbRead, &txs, // Note that '\x' gets parsed as a big.Int with value = 0
 		`SELECT tx.id, tx.to_forge_l1_txs_num, tx.position, tx.user_origin,
 		tx.from_idx, tx.effective_from_idx, tx.from_eth_addr, tx.from_bjj, tx.to_idx, tx.token_id,
 		tx.amount, (CASE WHEN tx.batch_num IS NULL THEN NULL WHEN tx.amount_success THEN tx.amount ELSE '\x' END) AS effective_amount,
@@ -715,7 +722,7 @@ func (hdb *HistoryDB) GetAllL1CoordinatorTxs() ([]common.L1Tx, error) {
 	// Since the query specifies that only coordinator txs are returned, it's safe to assume
 	// that returned txs will always have effective amounts
 	err := meddler.QueryAll(
-		hdb.db, &txs,
+		hdb.dbRead, &txs,
 		`SELECT tx.id, tx.to_forge_l1_txs_num, tx.position, tx.user_origin,
 		tx.from_idx, tx.effective_from_idx, tx.from_eth_addr, tx.from_bjj, tx.to_idx, tx.token_id,
 		tx.amount, tx.amount AS effective_amount,
@@ -730,7 +737,7 @@ func (hdb *HistoryDB) GetAllL1CoordinatorTxs() ([]common.L1Tx, error) {
 func (hdb *HistoryDB) GetAllL2Txs() ([]common.L2Tx, error) {
 	var txs []*common.L2Tx
 	err := meddler.QueryAll(
-		hdb.db, &txs,
+		hdb.dbRead, &txs,
 		`SELECT tx.id, tx.batch_num, tx.position,
 		tx.from_idx, tx.to_idx, tx.amount, tx.token_id,
 		tx.fee, tx.nonce, tx.type, tx.eth_block_num
@@ -743,7 +750,7 @@ func (hdb *HistoryDB) GetAllL2Txs() ([]common.L2Tx, error) {
 func (hdb *HistoryDB) GetUnforgedL1UserTxs(toForgeL1TxsNum int64) ([]common.L1Tx, error) {
 	var txs []*common.L1Tx
 	err := meddler.QueryAll(
-		hdb.db, &txs, // only L1 user txs can have batch_num set to null
+		hdb.dbRead, &txs, // only L1 user txs can have batch_num set to null
 		`SELECT tx.id, tx.to_forge_l1_txs_num, tx.position, tx.user_origin,
 		tx.from_idx, tx.from_eth_addr, tx.from_bjj, tx.to_idx, tx.token_id,
 		tx.amount, NULL AS effective_amount,
@@ -760,7 +767,7 @@ func (hdb *HistoryDB) GetUnforgedL1UserTxs(toForgeL1TxsNum int64) ([]common.L1Tx

 // GetLastTxsPosition for a given to_forge_l1_txs_num
 func (hdb *HistoryDB) GetLastTxsPosition(toForgeL1TxsNum int64) (int, error) {
-	row := hdb.db.QueryRow(
+	row := hdb.dbRead.QueryRow(
 		"SELECT position FROM tx WHERE to_forge_l1_txs_num = $1 ORDER BY position DESC;",
 		toForgeL1TxsNum,
 	)
@@ -774,15 +781,15 @@ func (hdb *HistoryDB) GetSCVars() (*common.RollupVariables, *common.AuctionVaria
 	var rollup common.RollupVariables
 	var auction common.AuctionVariables
 	var wDelayer common.WDelayerVariables
-	if err := meddler.QueryRow(hdb.db, &rollup,
+	if err := meddler.QueryRow(hdb.dbRead, &rollup,
 		"SELECT * FROM rollup_vars ORDER BY eth_block_num DESC LIMIT 1;"); err != nil {
 		return nil, nil, nil, tracerr.Wrap(err)
 	}
-	if err := meddler.QueryRow(hdb.db, &auction,
+	if err := meddler.QueryRow(hdb.dbRead, &auction,
 		"SELECT * FROM auction_vars ORDER BY eth_block_num DESC LIMIT 1;"); err != nil {
 		return nil, nil, nil, tracerr.Wrap(err)
 	}
-	if err := meddler.QueryRow(hdb.db, &wDelayer,
+	if err := meddler.QueryRow(hdb.dbRead, &wDelayer,
 		"SELECT * FROM wdelayer_vars ORDER BY eth_block_num DESC LIMIT 1;"); err != nil {
 		return nil, nil, nil, tracerr.Wrap(err)
 	}
@@ -827,7 +834,7 @@ func (hdb *HistoryDB) AddBucketUpdatesTest(d meddler.DB, bucketUpdates []common.
 func (hdb *HistoryDB) GetAllBucketUpdates() ([]common.BucketUpdate, error) {
 	var bucketUpdates []*common.BucketUpdate
 	err := meddler.QueryAll(
-		hdb.db, &bucketUpdates,
+		hdb.dbRead, &bucketUpdates,
 		`SELECT eth_block_num, num_bucket, block_stamp, withdrawals  
 		FROM bucket_update ORDER BY item_id;`,
 	)
@@ -853,7 +860,7 @@ func (hdb *HistoryDB) addTokenExchanges(d meddler.DB, tokenExchanges []common.To
 func (hdb *HistoryDB) GetAllTokenExchanges() ([]common.TokenExchange, error) {
 	var tokenExchanges []*common.TokenExchange
 	err := meddler.QueryAll(
-		hdb.db, &tokenExchanges,
+		hdb.dbRead, &tokenExchanges,
 		"SELECT eth_block_num, eth_addr, value_usd FROM token_exchange ORDER BY item_id;",
 	)
 	return db.SlicePtrsToSlice(tokenExchanges).([]common.TokenExchange), tracerr.Wrap(err)
@@ -881,7 +888,7 @@ func (hdb *HistoryDB) addEscapeHatchWithdrawals(d meddler.DB,
 func (hdb *HistoryDB) GetAllEscapeHatchWithdrawals() ([]common.WDelayerEscapeHatchWithdrawal, error) {
 	var escapeHatchWithdrawals []*common.WDelayerEscapeHatchWithdrawal
 	err := meddler.QueryAll(
-		hdb.db, &escapeHatchWithdrawals,
+		hdb.dbRead, &escapeHatchWithdrawals,
 		"SELECT eth_block_num, who_addr, to_addr, token_addr, amount FROM escape_hatch_withdrawal ORDER BY item_id;",
 	)
 	return db.SlicePtrsToSlice(escapeHatchWithdrawals).([]common.WDelayerEscapeHatchWithdrawal),
@@ -894,7 +901,7 @@ func (hdb *HistoryDB) GetAllEscapeHatchWithdrawals() ([]common.WDelayerEscapeHat
 // exist in the smart contracts.
 func (hdb *HistoryDB) SetInitialSCVars(rollup *common.RollupVariables,
 	auction *common.AuctionVariables, wDelayer *common.WDelayerVariables) error {
-	txn, err := hdb.db.Beginx()
+	txn, err := hdb.dbWrite.Beginx()
 	if err != nil {
 		return tracerr.Wrap(err)
 	}
@@ -978,7 +985,7 @@ func (hdb *HistoryDB) setExtraInfoForgedL1UserTxs(d sqlx.Ext, txs []common.L1Tx)
 // the pagination system of the API/DB depends on this.  Within blocks, all
 // items should also be in the correct order (Accounts, Tokens, Txs, etc.)
 func (hdb *HistoryDB) AddBlockSCData(blockData *common.BlockData) (err error) {
-	txn, err := hdb.db.Beginx()
+	txn, err := hdb.dbWrite.Beginx()
 	if err != nil {
 		return tracerr.Wrap(err)
 	}
@@ -1136,7 +1143,7 @@ func (hdb *HistoryDB) AddBlockSCData(blockData *common.BlockData) (err error) {
 func (hdb *HistoryDB) GetCoordinatorAPI(bidderAddr ethCommon.Address) (*CoordinatorAPI, error) {
 	coordinator := &CoordinatorAPI{}
 	err := meddler.QueryRow(
-		hdb.db, coordinator,
+		hdb.dbRead, coordinator,
 		"SELECT * FROM coordinator WHERE bidder_addr = $1 ORDER BY item_id DESC LIMIT 1;",
 		bidderAddr,
 	)
@@ -1145,14 +1152,14 @@ func (hdb *HistoryDB) GetCoordinatorAPI(bidderAddr ethCommon.Address) (*Coordina

 // AddAuctionVars insert auction vars into the DB
 func (hdb *HistoryDB) AddAuctionVars(auctionVars *common.AuctionVariables) error {
-	return tracerr.Wrap(meddler.Insert(hdb.db, "auction_vars", auctionVars))
+	return tracerr.Wrap(meddler.Insert(hdb.dbWrite, "auction_vars", auctionVars))
 }

 // GetTokensTest used to get tokens in a testing context
 func (hdb *HistoryDB) GetTokensTest() ([]TokenWithUSD, error) {
 	tokens := []*TokenWithUSD{}
 	if err := meddler.QueryAll(
-		hdb.db, &tokens,
+		hdb.dbRead, &tokens,
 		"SELECT * FROM TOKEN",
 	); err != nil {
 		return nil, tracerr.Wrap(err)
--- a/db/historydb/historydb_test.go
+++ b/db/historydb/historydb_test.go
@@ -39,12 +39,12 @@ func TestMain(m *testing.M) {
 	if err != nil {
 		panic(err)
 	}
-	historyDB = NewHistoryDB(db, nil)
+	historyDB = NewHistoryDB(db, db, nil)
 	if err != nil {
 		panic(err)
 	}
 	apiConnCon := dbUtils.NewAPICnnectionController(1, time.Second)
-	historyDBWithACC = NewHistoryDB(db, apiConnCon)
+	historyDBWithACC = NewHistoryDB(db, db, apiConnCon)
 	// Run tests
 	result := m.Run()
 	// Close DB
@@ -817,11 +817,11 @@ func TestSetExtraInfoForgedL1UserTxs(t *testing.T) {
 	}
 	// Add second batch to trigger the update of the batch_num,
 	// while avoiding the implicit call of setExtraInfoForgedL1UserTxs
-	err = historyDB.addBlock(historyDB.db, &blocks[1].Block)
+	err = historyDB.addBlock(historyDB.dbWrite, &blocks[1].Block)
 	require.NoError(t, err)
-	err = historyDB.addBatch(historyDB.db, &blocks[1].Rollup.Batches[0].Batch)
+	err = historyDB.addBatch(historyDB.dbWrite, &blocks[1].Rollup.Batches[0].Batch)
 	require.NoError(t, err)
-	err = historyDB.addAccounts(historyDB.db, blocks[1].Rollup.Batches[0].CreatedAccounts)
+	err = historyDB.addAccounts(historyDB.dbWrite, blocks[1].Rollup.Batches[0].CreatedAccounts)
 	require.NoError(t, err)

 	// Set the Effective{Amount,DepositAmount} of the L1UserTxs that are forged in the second block
@@ -831,7 +831,7 @@ func TestSetExtraInfoForgedL1UserTxs(t *testing.T) {
 	l1Txs[1].EffectiveAmount = big.NewInt(0)
 	l1Txs[2].EffectiveDepositAmount = big.NewInt(0)
 	l1Txs[2].EffectiveAmount = big.NewInt(0)
-	err = historyDB.setExtraInfoForgedL1UserTxs(historyDB.db, l1Txs)
+	err = historyDB.setExtraInfoForgedL1UserTxs(historyDB.dbWrite, l1Txs)
 	require.NoError(t, err)

 	dbL1Txs, err := historyDB.GetAllL1UserTxs()
@@ -918,10 +918,10 @@ func TestUpdateExitTree(t *testing.T) {
 		common.WithdrawInfo{Idx: 259, NumExitRoot: 3, InstantWithdraw: false,
 			Owner: tc.UsersByIdx[259].Addr, Token: tokenAddr},
 	)
-	err = historyDB.addBlock(historyDB.db, &block.Block)
+	err = historyDB.addBlock(historyDB.dbWrite, &block.Block)
 	require.NoError(t, err)

-	err = historyDB.updateExitTree(historyDB.db, block.Block.Num,
+	err = historyDB.updateExitTree(historyDB.dbWrite, block.Block.Num,
 		block.Rollup.Withdrawals, block.WDelayer.Withdrawals)
 	require.NoError(t, err)

@@ -951,10 +951,10 @@ func TestUpdateExitTree(t *testing.T) {
 			Token:  tokenAddr,
 			Amount: big.NewInt(80),
 		})
-	err = historyDB.addBlock(historyDB.db, &block.Block)
+	err = historyDB.addBlock(historyDB.dbWrite, &block.Block)
 	require.NoError(t, err)

-	err = historyDB.updateExitTree(historyDB.db, block.Block.Num,
+	err = historyDB.updateExitTree(historyDB.dbWrite, block.Block.Num,
 		block.Rollup.Withdrawals, block.WDelayer.Withdrawals)
 	require.NoError(t, err)

@@ -997,7 +997,7 @@ func TestGetBestBidCoordinator(t *testing.T) {
 			URL:         "bar",
 		},
 	}
-	err = historyDB.addCoordinators(historyDB.db, coords)
+	err = historyDB.addCoordinators(historyDB.dbWrite, coords)
 	require.NoError(t, err)

 	bids := []common.Bid{
@@ -1015,7 +1015,7 @@ func TestGetBestBidCoordinator(t *testing.T) {
 		},
 	}

-	err = historyDB.addBids(historyDB.db, bids)
+	err = historyDB.addBids(historyDB.dbWrite, bids)
 	require.NoError(t, err)

 	forger10, err := historyDB.GetBestBidCoordinator(10)
@@ -1053,7 +1053,7 @@ func TestAddBucketUpdates(t *testing.T) {
 			Withdrawals: big.NewInt(42),
 		},
 	}
-	err := historyDB.addBucketUpdates(historyDB.db, bucketUpdates)
+	err := historyDB.addBucketUpdates(historyDB.dbWrite, bucketUpdates)
 	require.NoError(t, err)
 	dbBucketUpdates, err := historyDB.GetAllBucketUpdates()
 	require.NoError(t, err)
@@ -1078,7 +1078,7 @@ func TestAddTokenExchanges(t *testing.T) {
 			ValueUSD:    67890,
 		},
 	}
-	err := historyDB.addTokenExchanges(historyDB.db, tokenExchanges)
+	err := historyDB.addTokenExchanges(historyDB.dbWrite, tokenExchanges)
 	require.NoError(t, err)
 	dbTokenExchanges, err := historyDB.GetAllTokenExchanges()
 	require.NoError(t, err)
@@ -1107,7 +1107,7 @@ func TestAddEscapeHatchWithdrawals(t *testing.T) {
 			Amount:      big.NewInt(20003),
 		},
 	}
-	err := historyDB.addEscapeHatchWithdrawals(historyDB.db, escapeHatchWithdrawals)
+	err := historyDB.addEscapeHatchWithdrawals(historyDB.dbWrite, escapeHatchWithdrawals)
 	require.NoError(t, err)
 	dbEscapeHatchWithdrawals, err := historyDB.GetAllEscapeHatchWithdrawals()
 	require.NoError(t, err)
--- a/db/l2db/apiqueries.go
+++ b/db/l2db/apiqueries.go
@@ -34,7 +34,7 @@ func (l2db *L2DB) GetAccountCreationAuthAPI(addr ethCommon.Address) (*AccountCre
 	defer l2db.apiConnCon.Release()
 	auth := new(AccountCreationAuthAPI)
 	return auth, tracerr.Wrap(meddler.QueryRow(
-		l2db.db, auth,
+		l2db.dbRead, auth,
 		"SELECT * FROM account_creation_auth WHERE eth_addr = $1;",
 		addr,
 	))
@@ -49,7 +49,7 @@ func (l2db *L2DB) AddTxAPI(tx *PoolL2TxWrite) error {
 	}
 	defer l2db.apiConnCon.Release()

-	row := l2db.db.QueryRow(`SELECT
+	row := l2db.dbRead.QueryRow(`SELECT
 		($1::NUMERIC * token.usd * fee_percentage($2::NUMERIC)) /
 			(10.0 ^ token.decimals::NUMERIC)
 		FROM token WHERE token.token_id = $3;`,
@@ -84,7 +84,7 @@ func (l2db *L2DB) AddTxAPI(tx *PoolL2TxWrite) error {
 		namesPart, valuesPart,
 		len(values)+1, len(values)+2) //nolint:gomnd
 	values = append(values, common.PoolL2TxStatePending, l2db.maxTxs)
-	res, err := l2db.db.Exec(q, values...)
+	res, err := l2db.dbWrite.Exec(q, values...)
 	if err != nil {
 		return tracerr.Wrap(err)
 	}
@@ -118,7 +118,7 @@ func (l2db *L2DB) GetTxAPI(txID common.TxID) (*PoolTxAPI, error) {
 	defer l2db.apiConnCon.Release()
 	tx := new(PoolTxAPI)
 	return tx, tracerr.Wrap(meddler.QueryRow(
-		l2db.db, tx,
+		l2db.dbRead, tx,
 		selectPoolTxAPI+"WHERE tx_id = $1;",
 		txID,
 	))
--- a/db/l2db/l2db.go
+++ b/db/l2db/l2db.go
@@ -21,7 +21,8 @@ import (
 // L2DB stores L2 txs and authorization registers received by the coordinator and keeps them until they are no longer relevant
 // due to them being forged or invalid after a safety period
 type L2DB struct {
-	db           *sqlx.DB
+	dbRead       *sqlx.DB
+	dbWrite      *sqlx.DB
 	safetyPeriod common.BatchNum
 	ttl          time.Duration
 	maxTxs       uint32 // limit of txs that are accepted in the pool
@@ -33,7 +34,7 @@ type L2DB struct {
 // To create it, it's needed db connection, safety period expressed in batches,
 // maxTxs that the DB should have and TTL (time to live) for pending txs.
 func NewL2DB(
-	db *sqlx.DB,
+	dbRead, dbWrite *sqlx.DB,
 	safetyPeriod common.BatchNum,
 	maxTxs uint32,
 	minFeeUSD float64,
@@ -41,7 +42,8 @@ func NewL2DB(
 	apiConnCon *db.APIConnectionController,
 ) *L2DB {
 	return &L2DB{
-		db:           db,
+		dbRead:       dbRead,
+		dbWrite:      dbWrite,
 		safetyPeriod: safetyPeriod,
 		ttl:          TTL,
 		maxTxs:       maxTxs,
@@ -53,7 +55,7 @@ func NewL2DB(
 // DB returns a pointer to the L2DB.db. This method should be used only for
 // internal testing purposes.
 func (l2db *L2DB) DB() *sqlx.DB {
-	return l2db.db
+	return l2db.dbWrite
 }

 // MinFeeUSD returns the minimum fee in USD that is required to accept txs into
@@ -64,7 +66,7 @@ func (l2db *L2DB) MinFeeUSD() float64 {

 // AddAccountCreationAuth inserts an account creation authorization into the DB
 func (l2db *L2DB) AddAccountCreationAuth(auth *common.AccountCreationAuth) error {
-	_, err := l2db.db.Exec(
+	_, err := l2db.dbWrite.Exec(
 		`INSERT INTO account_creation_auth (eth_addr, bjj, signature)
 		VALUES ($1, $2, $3);`,
 		auth.EthAddr, auth.BJJ, auth.Signature,
@@ -76,7 +78,7 @@ func (l2db *L2DB) AddAccountCreationAuth(auth *common.AccountCreationAuth) error
 func (l2db *L2DB) GetAccountCreationAuth(addr ethCommon.Address) (*common.AccountCreationAuth, error) {
 	auth := new(common.AccountCreationAuth)
 	return auth, tracerr.Wrap(meddler.QueryRow(
-		l2db.db, auth,
+		l2db.dbRead, auth,
 		"SELECT * FROM account_creation_auth WHERE eth_addr = $1;",
 		addr,
 	))
@@ -105,7 +107,7 @@ func (l2db *L2DB) UpdateTxsInfo(txs []common.PoolL2Tx) error {
 		WHERE tx_pool.tx_id = tx_update.id;
 	`
 	if len(txUpdates) > 0 {
-		if _, err := sqlx.NamedExec(l2db.db, query, txUpdates); err != nil {
+		if _, err := sqlx.NamedExec(l2db.dbWrite, query, txUpdates); err != nil {
 			return tracerr.Wrap(err)
 		}
 	}
@@ -164,7 +166,7 @@ func NewPoolL2TxWriteFromPoolL2Tx(tx *common.PoolL2Tx) *PoolL2TxWrite {
 func (l2db *L2DB) AddTxTest(tx *common.PoolL2Tx) error {
 	insertTx := NewPoolL2TxWriteFromPoolL2Tx(tx)
 	// insert tx
-	return tracerr.Wrap(meddler.Insert(l2db.db, "tx_pool", insertTx))
+	return tracerr.Wrap(meddler.Insert(l2db.dbWrite, "tx_pool", insertTx))
 }

 // selectPoolTxCommon select part of queries to get common.PoolL2Tx
@@ -181,7 +183,7 @@ FROM tx_pool INNER JOIN token ON tx_pool.token_id = token.token_id `
 func (l2db *L2DB) GetTx(txID common.TxID) (*common.PoolL2Tx, error) {
 	tx := new(common.PoolL2Tx)
 	return tx, tracerr.Wrap(meddler.QueryRow(
-		l2db.db, tx,
+		l2db.dbRead, tx,
 		selectPoolTxCommon+"WHERE tx_id = $1;",
 		txID,
 	))
@@ -191,7 +193,7 @@ func (l2db *L2DB) GetTx(txID common.TxID) (*common.PoolL2Tx, error) {
 func (l2db *L2DB) GetPendingTxs() ([]common.PoolL2Tx, error) {
 	var txs []*common.PoolL2Tx
 	err := meddler.QueryAll(
-		l2db.db, &txs,
+		l2db.dbRead, &txs,
 		selectPoolTxCommon+"WHERE state = $1",
 		common.PoolL2TxStatePending,
 	)
@@ -216,8 +218,8 @@ func (l2db *L2DB) StartForging(txIDs []common.TxID, batchNum common.BatchNum) er
 	if err != nil {
 		return tracerr.Wrap(err)
 	}
-	query = l2db.db.Rebind(query)
-	_, err = l2db.db.Exec(query, args...)
+	query = l2db.dbWrite.Rebind(query)
+	_, err = l2db.dbWrite.Exec(query, args...)
 	return tracerr.Wrap(err)
 }

@@ -239,8 +241,8 @@ func (l2db *L2DB) DoneForging(txIDs []common.TxID, batchNum common.BatchNum) err
 	if err != nil {
 		return tracerr.Wrap(err)
 	}
-	query = l2db.db.Rebind(query)
-	_, err = l2db.db.Exec(query, args...)
+	query = l2db.dbWrite.Rebind(query)
+	_, err = l2db.dbWrite.Exec(query, args...)
 	return tracerr.Wrap(err)
 }

@@ -261,8 +263,8 @@ func (l2db *L2DB) InvalidateTxs(txIDs []common.TxID, batchNum common.BatchNum) e
 	if err != nil {
 		return tracerr.Wrap(err)
 	}
-	query = l2db.db.Rebind(query)
-	_, err = l2db.db.Exec(query, args...)
+	query = l2db.dbWrite.Rebind(query)
+	_, err = l2db.dbWrite.Exec(query, args...)
 	return tracerr.Wrap(err)
 }

@@ -270,7 +272,7 @@ func (l2db *L2DB) InvalidateTxs(txIDs []common.TxID, batchNum common.BatchNum) e
 // of unique FromIdx
 func (l2db *L2DB) GetPendingUniqueFromIdxs() ([]common.Idx, error) {
 	var idxs []common.Idx
-	rows, err := l2db.db.Query(`SELECT DISTINCT from_idx FROM tx_pool
+	rows, err := l2db.dbRead.Query(`SELECT DISTINCT from_idx FROM tx_pool
 		WHERE state = $1;`, common.PoolL2TxStatePending)
 	if err != nil {
 		return nil, tracerr.Wrap(err)
@@ -311,7 +313,7 @@ func (l2db *L2DB) InvalidateOldNonces(updatedAccounts []common.IdxNonce, batchNu
 	// named query which works with slices, and doens't handle an extra
 	// individual argument.
 	query := fmt.Sprintf(invalidateOldNoncesQuery, batchNum)
-	if _, err := sqlx.NamedExec(l2db.db, query, updatedAccounts); err != nil {
+	if _, err := sqlx.NamedExec(l2db.dbWrite, query, updatedAccounts); err != nil {
 		return tracerr.Wrap(err)
 	}
 	return nil
@@ -320,7 +322,7 @@ func (l2db *L2DB) InvalidateOldNonces(updatedAccounts []common.IdxNonce, batchNu
 // Reorg updates the state of txs that were updated in a batch that has been discarted due to a blockchain reorg.
 // The state of the affected txs can change form Forged -> Pending or from Invalid -> Pending
 func (l2db *L2DB) Reorg(lastValidBatch common.BatchNum) error {
-	_, err := l2db.db.Exec(
+	_, err := l2db.dbWrite.Exec(
 		`UPDATE tx_pool SET batch_num = NULL, state = $1
 		WHERE (state = $2 OR state = $3 OR state = $4) AND batch_num > $5`,
 		common.PoolL2TxStatePending,
@@ -336,7 +338,7 @@ func (l2db *L2DB) Reorg(lastValidBatch common.BatchNum) error {
 // it also deletes pending txs that have been in the L2DB for longer than the ttl if maxTxs has been exceeded
 func (l2db *L2DB) Purge(currentBatchNum common.BatchNum) (err error) {
 	now := time.Now().UTC().Unix()
-	_, err = l2db.db.Exec(
+	_, err = l2db.dbWrite.Exec(
 		`DELETE FROM tx_pool WHERE (
 			batch_num < $1 AND (state = $2 OR state = $3)
 		) OR (
@@ -357,7 +359,7 @@ func (l2db *L2DB) Purge(currentBatchNum common.BatchNum) (err error) {
 // the `external_delete` column.  An external process can set this column to
 // true to instruct the coordinator to delete the tx when possible.
 func (l2db *L2DB) PurgeByExternalDelete() error {
-	_, err := l2db.db.Exec(
+	_, err := l2db.dbWrite.Exec(
 		`DELETE from tx_pool WHERE (external_delete = true AND state = $1);`,
 		common.PoolL2TxStatePending,
 	)
--- a/db/l2db/l2db_test.go
+++ b/db/l2db/l2db_test.go
@@ -37,11 +37,11 @@ func TestMain(m *testing.M) {
 	if err != nil {
 		panic(err)
 	}
-	l2DB = NewL2DB(db, 10, 1000, 0.0, 24*time.Hour, nil)
+	l2DB = NewL2DB(db, db, 10, 1000, 0.0, 24*time.Hour, nil)
 	apiConnCon := dbUtils.NewAPICnnectionController(1, time.Second)
-	l2DBWithACC = NewL2DB(db, 10, 1000, 0.0, 24*time.Hour, apiConnCon)
+	l2DBWithACC = NewL2DB(db, db, 10, 1000, 0.0, 24*time.Hour, apiConnCon)
 	test.WipeDB(l2DB.DB())
-	historyDB = historydb.NewHistoryDB(db, nil)
+	historyDB = historydb.NewHistoryDB(db, db, nil)
 	// Run tests
 	result := m.Run()
 	// Close DB
@@ -660,7 +660,7 @@ func TestPurge(t *testing.T) {
 	}
 	// Set batchNum keeped txs
 	for i := range keepedIDs {
-		_, err = l2DB.db.Exec(
+		_, err = l2DB.dbWrite.Exec(
 			"UPDATE tx_pool SET batch_num = $1 WHERE tx_id = $2;",
 			safeBatchNum, keepedIDs[i],
 		)
@@ -679,7 +679,7 @@ func TestPurge(t *testing.T) {
 	deleteTimestamp := time.Unix(time.Now().UTC().Unix()-int64(l2DB.ttl.Seconds()+float64(4*time.Second)), 0)
 	for _, id := range afterTTLIDs {
 		// Set timestamp
-		_, err = l2DB.db.Exec(
+		_, err = l2DB.dbWrite.Exec(
 			"UPDATE tx_pool SET timestamp = $1, state = $2 WHERE tx_id = $3;",
 			deleteTimestamp, common.PoolL2TxStatePending, id,
 		)
@@ -797,7 +797,7 @@ func TestPurgeByExternalDelete(t *testing.T) {
 	require.NoError(t, l2DB.StartForging(
 		[]common.TxID{txs[4].TxID, txs[5].TxID, txs[6].TxID, txs[7].TxID},
 		1))
-	_, err = l2DB.db.Exec(
+	_, err = l2DB.dbWrite.Exec(
 		`UPDATE tx_pool SET external_delete = true WHERE
 			tx_id IN ($1, $2, $3, $4)
 		;`,
--- a/node/node.go
+++ b/node/node.go
@@ -62,27 +62,47 @@ type Node struct {
 	sync *synchronizer.Synchronizer

 	// General
-	cfg     *config.Node
-	mode    Mode
-	sqlConn *sqlx.DB
-	ctx     context.Context
-	wg      sync.WaitGroup
-	cancel  context.CancelFunc
+	cfg          *config.Node
+	mode         Mode
+	sqlConnRead  *sqlx.DB
+	sqlConnWrite *sqlx.DB
+	ctx          context.Context
+	wg           sync.WaitGroup
+	cancel       context.CancelFunc
 }

 // NewNode creates a Node
 func NewNode(mode Mode, cfg *config.Node) (*Node, error) {
 	meddler.Debug = cfg.Debug.MeddlerLogs
 	// Stablish DB connection
-	db, err := dbUtils.InitSQLDB(
-		cfg.PostgreSQL.Port,
-		cfg.PostgreSQL.Host,
-		cfg.PostgreSQL.User,
-		cfg.PostgreSQL.Password,
-		cfg.PostgreSQL.Name,
+	dbWrite, err := dbUtils.InitSQLDB(
+		cfg.PostgreSQL.PortWrite,
+		cfg.PostgreSQL.HostWrite,
+		cfg.PostgreSQL.UserWrite,
+		cfg.PostgreSQL.PasswordWrite,
+		cfg.PostgreSQL.NameWrite,
 	)
 	if err != nil {
-		return nil, tracerr.Wrap(err)
+		return nil, tracerr.Wrap(fmt.Errorf("dbUtils.InitSQLDB: %w", err))
+	}
+	var dbRead *sqlx.DB
+	if cfg.PostgreSQL.HostRead == "" {
+		dbRead = dbWrite
+	} else if cfg.PostgreSQL.HostRead == cfg.PostgreSQL.HostWrite {
+		return nil, tracerr.Wrap(fmt.Errorf(
+			"PostgreSQL.HostRead and PostgreSQL.HostWrite must be different",
+		))
+	} else {
+		dbRead, err = dbUtils.InitSQLDB(
+			cfg.PostgreSQL.PortRead,
+			cfg.PostgreSQL.HostRead,
+			cfg.PostgreSQL.UserRead,
+			cfg.PostgreSQL.PasswordRead,
+			cfg.PostgreSQL.NameRead,
+		)
+		if err != nil {
+			return nil, tracerr.Wrap(fmt.Errorf("dbUtils.InitSQLDB: %w", err))
+		}
 	}
 	var apiConnCon *dbUtils.APIConnectionController
 	if cfg.API.Explorer || mode == ModeCoordinator {
@@ -92,7 +112,7 @@ func NewNode(mode Mode, cfg *config.Node) (*Node, error) {
 		)
 	}

-	historyDB := historydb.NewHistoryDB(db, apiConnCon)
+	historyDB := historydb.NewHistoryDB(dbRead, dbWrite, apiConnCon)

 	ethClient, err := ethclient.Dial(cfg.Web3.URL)
 	if err != nil {
@@ -201,7 +221,7 @@ func NewNode(mode Mode, cfg *config.Node) (*Node, error) {
 	var l2DB *l2db.L2DB
 	if mode == ModeCoordinator {
 		l2DB = l2db.NewL2DB(
-			db,
+			dbRead, dbWrite,
 			cfg.Coordinator.L2DB.SafetyPeriod,
 			cfg.Coordinator.L2DB.MaxTxs,
 			cfg.Coordinator.L2DB.MinFeeUSD,
@@ -391,7 +411,8 @@ func NewNode(mode Mode, cfg *config.Node) (*Node, error) {
 		sync:         sync,
 		cfg:          cfg,
 		mode:         mode,
-		sqlConn:      db,
+		sqlConnRead:  dbRead,
+		sqlConnWrite: dbWrite,
 		ctx:          ctx,
 		cancel:       cancel,
 	}, nil
--- a/priceupdater/priceupdater_test.go
+++ b/priceupdater/priceupdater_test.go
@@ -20,7 +20,7 @@ func TestPriceUpdater(t *testing.T) {
 	pass := os.Getenv("POSTGRES_PASS")
 	db, err := dbUtils.InitSQLDB(5432, "localhost", "hermez", pass, "hermez")
 	assert.NoError(t, err)
-	historyDB := historydb.NewHistoryDB(db, nil)
+	historyDB := historydb.NewHistoryDB(db, db, nil)
 	// Clean DB
 	test.WipeDB(historyDB.DB())
 	// Populate DB
--- a/synchronizer/synchronizer_test.go
+++ b/synchronizer/synchronizer_test.go
@@ -315,7 +315,7 @@ func newTestModules(t *testing.T) (*statedb.StateDB, *historydb.HistoryDB) {
 	pass := os.Getenv("POSTGRES_PASS")
 	db, err := dbUtils.InitSQLDB(5432, "localhost", "hermez", pass, "hermez")
 	require.NoError(t, err)
-	historyDB := historydb.NewHistoryDB(db, nil)
+	historyDB := historydb.NewHistoryDB(db, db, nil)
 	// Clear DB
 	test.WipeDB(historyDB.DB())

--- a/test/zkproof/flows_test.go
+++ b/test/zkproof/flows_test.go
@@ -38,7 +38,7 @@ func addTokens(t *testing.T, tc *til.Context, db *sqlx.DB) {
 		})
 	}

-	hdb := historydb.NewHistoryDB(db, nil)
+	hdb := historydb.NewHistoryDB(db, db, nil)
 	assert.NoError(t, hdb.AddBlock(&common.Block{
 		Num: 1,
 	}))
@@ -75,7 +75,7 @@ func initTxSelector(t *testing.T, chainID uint16, hermezContractAddr ethCommon.A
 	pass := os.Getenv("POSTGRES_PASS")
 	db, err := dbUtils.InitSQLDB(5432, "localhost", "hermez", pass, "hermez")
 	require.NoError(t, err)
-	l2DB := l2db.NewL2DB(db, 10, 100, 0.0, 24*time.Hour, nil)
+	l2DB := l2db.NewL2DB(db, db, 10, 100, 0.0, 24*time.Hour, nil)

 	dir, err := ioutil.TempDir("", "tmpSyncDB")
 	require.NoError(t, err)
--- a/txselector/txselector_test.go
+++ b/txselector/txselector_test.go
@@ -29,7 +29,7 @@ func initTest(t *testing.T, chainID uint16, hermezContractAddr ethCommon.Address
 	pass := os.Getenv("POSTGRES_PASS")
 	db, err := dbUtils.InitSQLDB(5432, "localhost", "hermez", pass, "hermez")
 	require.NoError(t, err)
-	l2DB := l2db.NewL2DB(db, 10, 100, 0.0, 24*time.Hour, nil)
+	l2DB := l2db.NewL2DB(db, db, 10, 100, 0.0, 24*time.Hour, nil)

 	dir, err := ioutil.TempDir("", "tmpdb")
 	require.NoError(t, err)
@@ -106,7 +106,7 @@ func addTokens(t *testing.T, tc *til.Context, db *sqlx.DB) {
 		})
 	}

-	hdb := historydb.NewHistoryDB(db, nil)
+	hdb := historydb.NewHistoryDB(db, db, nil)
 	assert.NoError(t, hdb.AddBlock(&common.Block{
 		Num: 1,
 	}))