Add semaphore for API queries to SQL

api/accountcreationauths.go

@@ -26,7 +26,7 @@ func (a *API) postAccountCreationAuth(c *gin.Context) {
 		return
 	}
 	// Insert to DB
-	if err := a.l2.AddAccountCreationAuth(commonAuth); err != nil {
+	if err := a.l2.AddAccountCreationAuthAPI(commonAuth); err != nil {
 		retSQLErr(err, c)
 		return
 	}

api/api_test.go

@@ -27,6 +27,7 @@ import (
 	"github.com/hermeznetwork/hermez-node/test/til"
 	"github.com/hermeznetwork/hermez-node/test/txsets"
 	"github.com/hermeznetwork/tracerr"
+	"github.com/stretchr/testify/require"
 )
 
 // Pendinger is an interface that allows getting last returned item ID and PendingItems to be used for building fromItem
@@ -199,7 +200,8 @@ func TestMain(m *testing.M) {
 	if err != nil {
 		panic(err)
 	}
-	hdb := historydb.NewHistoryDB(database)
+	apiConnCon := db.NewAPICnnectionController(1, time.Second)
+	hdb := historydb.NewHistoryDB(database, apiConnCon)
 	if err != nil {
 		panic(err)
 	}
@@ -218,7 +220,7 @@ func TestMain(m *testing.M) {
 		panic(err)
 	}
 	// L2DB
-	l2DB := l2db.NewL2DB(database, 10, 1000, 24*time.Hour)
+	l2DB := l2db.NewL2DB(database, 10, 1000, 24*time.Hour, apiConnCon)
 	test.WipeDB(l2DB.DB()) // this will clean HistoryDB and L2DB
 	// Config (smart contract constants)
 	chainID := uint16(0)
@@ -574,6 +576,73 @@ func TestMain(m *testing.M) {
 	os.Exit(result)
 }
 
+func TestTimeout(t *testing.T) {
+	pass := os.Getenv("POSTGRES_PASS")
+	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)
+	require.NoError(t, err)
+	// L2DB
+	l2DBTO := l2db.NewL2DB(databaseTO, 10, 1000, 24*time.Hour, apiConnConTO)
+
+	// API
+	apiGinTO := gin.Default()
+	apiGinTO.GET("/wait", func(c *gin.Context) {
+		cancel, err := apiConnConTO.Acquire()
+		defer cancel()
+		require.NoError(t, err)
+		defer apiConnConTO.Release()
+		time.Sleep(200 * time.Millisecond)
+	})
+	// Start server
+	serverTO := &http.Server{Addr: ":4444", Handler: apiGinTO}
+	go func() {
+		if err := serverTO.ListenAndServe(); err != nil && tracerr.Unwrap(err) != http.ErrServerClosed {
+			require.NoError(t, err)
+		}
+	}()
+	_config := getConfigTest(0)
+	_, err = NewAPI(
+		true,
+		true,
+		apiGinTO,
+		hdbTO,
+		nil,
+		l2DBTO,
+		&_config,
+	)
+	require.NoError(t, err)
+
+	client := &http.Client{}
+	httpReq, err := http.NewRequest("GET", "http://localhost:4444/tokens", nil)
+	require.NoError(t, err)
+	httpReqWait, err := http.NewRequest("GET", "http://localhost:4444/wait", nil)
+	require.NoError(t, err)
+	// Request that will get timed out
+	go func() {
+		resp, err := client.Do(httpReq)
+		require.NoError(t, err)
+		require.Equal(t, http.StatusServiceUnavailable, resp.StatusCode)
+		defer resp.Body.Close() //nolint
+		require.NoError(t, err)
+		body, err := ioutil.ReadAll(resp.Body)
+		require.NoError(t, err)
+		// Unmarshal body into return struct
+		msg := &errorMsg{}
+		err = json.Unmarshal(body, msg)
+		require.NoError(t, err)
+		// Check that the error was the expected down
+		require.Equal(t, errSQLTimeout, msg.Message)
+		// Stop server
+		require.NoError(t, serverTO.Shutdown(context.Background()))
+		require.NoError(t, databaseTO.Close())
+	}()
+	// Request that will make the API busy
+	_, err = client.Do(httpReqWait)
+	require.NoError(t, err)
+}
+
 func doGoodReqPaginated(
 	path, order string,
 	iterStruct Pendinger,

api/batch.go

@@ -108,7 +108,7 @@ func (a *API) getFullBatch(c *gin.Context) {
 	}
 	// Fetch txs forged in the batch from historyDB
 	maxTxsPerBatch := uint(2048) //nolint:gomnd
-	txs, _, err := a.h.GetHistoryTxs(
+	txs, _, err := a.h.GetTxsAPI(
 		nil, nil, nil, nil, batchNum, nil, nil, &maxTxsPerBatch, historydb.OrderAsc,
 	)
 	if err != nil && tracerr.Unwrap(err) != sql.ErrNoRows {

api/handlers.go

@@ -30,6 +30,12 @@ const (
 
 	// Error for duplicated key
 	errDuplicatedKey = "Item already exists"
+
+	// Error for timeout due to SQL connection
+	errSQLTimeout = "The node is under heavy preasure, please try again later"
+
+	// Error message returned when context reaches timeout
+	errCtxTimeout = "context deadline exceeded"
 )
 
 var (
@@ -38,16 +44,20 @@ var (
 )
 
 func retSQLErr(err error, c *gin.Context) {
-	log.Warn("HTTP API SQL request error", "err", err)
+	log.Warnw("HTTP API SQL request error", "err", err)
-	if sqlErr, ok := tracerr.Unwrap(err).(*pq.Error); ok {
+	errMsg := tracerr.Unwrap(err).Error()
+	if errMsg == errCtxTimeout {
+		c.JSON(http.StatusServiceUnavailable, errorMsg{
+			Message: errSQLTimeout,
+		})
+	} else if sqlErr, ok := tracerr.Unwrap(err).(*pq.Error); ok {
 		// https://www.postgresql.org/docs/current/errcodes-appendix.html
 		if sqlErr.Code == "23505" {
 			c.JSON(http.StatusInternalServerError, errorMsg{
 				Message: errDuplicatedKey,
 			})
 		}
-	}
+	} else if tracerr.Unwrap(err) == sql.ErrNoRows {
-	if tracerr.Unwrap(err) == sql.ErrNoRows {
 		c.JSON(http.StatusNotFound, errorMsg{
 			Message: err.Error(),
 		})
@@ -59,7 +69,7 @@ func retSQLErr(err error, c *gin.Context) {
 }
 
 func retBadReq(err error, c *gin.Context) {
-	log.Warn("HTTP API Bad request error", "err", err)
+	log.Warnw("HTTP API Bad request error", "err", err)
 	c.JSON(http.StatusBadRequest, errorMsg{
 		Message: err.Error(),
 	})

api/slots.go

@@ -97,12 +97,12 @@ func (a *API) getSlot(c *gin.Context) {
 		retBadReq(err, c)
 		return
 	}
-	currentBlock, err := a.h.GetLastBlock()
+	currentBlock, err := a.h.GetLastBlockAPI()
 	if err != nil {
 		retBadReq(err, c)
 		return
 	}
-	auctionVars, err := a.h.GetAuctionVars()
+	auctionVars, err := a.h.GetAuctionVarsAPI()
 	if err != nil {
 		retBadReq(err, c)
 		return
@@ -200,12 +200,12 @@ func (a *API) getSlots(c *gin.Context) {
 		return
 	}
 
-	currentBlock, err := a.h.GetLastBlock()
+	currentBlock, err := a.h.GetLastBlockAPI()
 	if err != nil {
 		retBadReq(err, c)
 		return
 	}
-	auctionVars, err := a.h.GetAuctionVars()
+	auctionVars, err := a.h.GetAuctionVarsAPI()
 	if err != nil {
 		retBadReq(err, c)
 		return
@@ -220,13 +220,13 @@ func (a *API) getSlots(c *gin.Context) {
 			retBadReq(errors.New("It is necessary to add maxSlotNum filter"), c)
 			return
 		} else if *finishedAuction {
-			currentBlock, err := a.h.GetLastBlock()
+			currentBlock, err := a.h.GetLastBlockAPI()
 			if err != nil {
 				retBadReq(err, c)
 				return
 			}
 			currentSlot := a.getCurrentSlot(currentBlock.Num)
-			auctionVars, err := a.h.GetAuctionVars()
+			auctionVars, err := a.h.GetAuctionVarsAPI()
 			if err != nil {
 				retBadReq(err, c)
 				return

api/state.go

@@ -141,7 +141,7 @@ func (a *API) UpdateNetworkInfo(
 	a.status.Network.NextForgers = nextForgers
 
 	// Update buckets withdrawals
-	bucketsUpdate, err := a.h.GetBucketUpdates()
+	bucketsUpdate, err := a.h.GetBucketUpdatesAPI()
 	if tracerr.Unwrap(err) == sql.ErrNoRows {
 		bucketsUpdate = nil
 	} else if err != nil {
@@ -201,7 +201,7 @@ func (a *API) getNextForgers(lastBlock common.Block, currentSlot, lastClosedSlot
 		}}
 	} else {
 		// Get all the relevant updates from the DB
-		minBidInfo, err = a.h.GetAuctionVarsUntilSetSlotNum(lastClosedSlot, int(lastClosedSlot-currentSlot)+1)
+		minBidInfo, err = a.h.GetAuctionVarsUntilSetSlotNumAPI(lastClosedSlot, int(lastClosedSlot-currentSlot)+1)
 		if err != nil {
 			return nil, tracerr.Wrap(err)
 		}
@@ -279,7 +279,7 @@ func (a *API) UpdateMetrics() error {
 	}
 	batchNum := a.status.Network.LastBatch.BatchNum
 	a.status.RUnlock()
-	metrics, err := a.h.GetMetrics(batchNum)
+	metrics, err := a.h.GetMetricsAPI(batchNum)
 	if err != nil {
 		return tracerr.Wrap(err)
 	}
@@ -293,7 +293,7 @@ func (a *API) UpdateMetrics() error {
 
 // UpdateRecommendedFee update Status.RecommendedFee information
 func (a *API) UpdateRecommendedFee() error {
-	feeExistingAccount, err := a.h.GetAvgTxFee()
+	feeExistingAccount, err := a.h.GetAvgTxFeeAPI()
 	if err != nil {
 		return tracerr.Wrap(err)
 	}

api/token.go

@@ -22,7 +22,7 @@ func (a *API) getToken(c *gin.Context) {
 	}
 	tokenID := common.TokenID(*tokenIDUint)
 	// Fetch token from historyDB
-	token, err := a.h.GetToken(tokenID)
+	token, err := a.h.GetTokenAPI(tokenID)
 	if err != nil {
 		retSQLErr(err, c)
 		return
@@ -45,7 +45,7 @@ func (a *API) getTokens(c *gin.Context) {
 		return
 	}
 	// Fetch exits from historyDB
-	tokens, pendingItems, err := a.h.GetTokens(
+	tokens, pendingItems, err := a.h.GetTokensAPI(
 		tokenIDs, symbols, name, fromItem, limit, order,
 	)
 	if err != nil {

api/txshistory.go

@@ -34,7 +34,7 @@ func (a *API) getHistoryTxs(c *gin.Context) {
 	}
 
 	// Fetch txs from historyDB
-	txs, pendingItems, err := a.h.GetHistoryTxs(
+	txs, pendingItems, err := a.h.GetTxsAPI(
 		addr, bjj, tokenID, idx, batchNum, txType, fromItem, limit, order,
 	)
 	if err != nil {
@@ -61,7 +61,7 @@ func (a *API) getHistoryTx(c *gin.Context) {
 		return
 	}
 	// Fetch tx from historyDB
-	tx, err := a.h.GetHistoryTx(txID)
+	tx, err := a.h.GetTxAPI(txID)
 	if err != nil {
 		retSQLErr(err, c)
 		return

api/txspool.go

@@ -28,7 +28,7 @@ func (a *API) postPoolTx(c *gin.Context) {
 		return
 	}
 	// Insert to DB
-	if err := a.l2.AddTx(writeTx); err != nil {
+	if err := a.l2.AddTxAPI(writeTx); err != nil {
 		retSQLErr(err, c)
 		return
 	}

cli/node/cfg.buidler.toml

@@ -3,6 +3,8 @@ Address = "localhost:8086"
 Explorer = true
 UpdateMetricsInterval = "10s"
 UpdateRecommendedFeeInterval = "10s"
+MaxSQLConnections = 100
+SQLConnectionTimeout = "2s"
 
 [PriceUpdater]
 Interval = "10s"

config/config.go

@@ -201,9 +201,14 @@ type Node struct {
 		// UpdateMetricsInterval is the interval between updates of the
 		// API metrics
 		UpdateMetricsInterval Duration
-		// UpdateMetricsInterval is the interval between updates of the
+		// UpdateRecommendedFeeInterval is the interval between updates of the
 		// recommended fees
 		UpdateRecommendedFeeInterval Duration
+		// Maximum concurrent connections allowed between API and SQL
+		MaxSQLConnections int `validate:"required"`
+		// SQLConnectionTimeout is the maximum amount of time that an API request
+		// can wait to stablish a SQL connection
+		SQLConnectionTimeout Duration
 	} `validate:"required"`
 	Debug struct {
 		// APIAddress is the address where the debugAPI will listen if

coordinator/coordinator_test.go

@@ -104,8 +104,8 @@ 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, 24*time.Hour)
+	l2DB := l2db.NewL2DB(db, 10, 100, 24*time.Hour, nil)
-	historyDB := historydb.NewHistoryDB(db)
+	historyDB := historydb.NewHistoryDB(db, nil)
 
 	txSelDBPath, err = ioutil.TempDir("", "tmpTxSelDB")
 	require.NoError(t, err)

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, 24*time.Hour)
+	return l2db.NewL2DB(db, 10, 100, 24*time.Hour, nil)
 }
 
 func newStateDB(t *testing.T) *statedb.LocalStateDB {

db/historydb/historydb.go

@@ -1,8 +1,6 @@
 package historydb
 
 import (
-	"errors"
-	"fmt"
 	"math"
 	"math/big"
 	"strings"
@@ -11,7 +9,6 @@ import (
 	"github.com/hermeznetwork/hermez-node/common"
 	"github.com/hermeznetwork/hermez-node/db"
 	"github.com/hermeznetwork/tracerr"
-	"github.com/iden3/go-iden3-crypto/babyjub"
 	"github.com/jmoiron/sqlx"
 
 	//nolint:errcheck // driver for postgres DB
@@ -31,11 +28,12 @@ const (
 // HistoryDB persist the historic of the rollup
 type HistoryDB struct {
 	db         *sqlx.DB
+	apiConnCon *db.APIConnectionController
 }
 
 // NewHistoryDB initialize the DB
-func NewHistoryDB(db *sqlx.DB) *HistoryDB {
+func NewHistoryDB(db *sqlx.DB, apiConnCon *db.APIConnectionController) *HistoryDB {
-	return &HistoryDB{db: db}
+	return &HistoryDB{db: db, apiConnCon: apiConnCon}
 }
 
 // DB returns a pointer to the L2DB.db. This method should be used only for
@@ -87,8 +85,8 @@ func (hdb *HistoryDB) GetAllBlocks() ([]common.Block, error) {
 	return db.SlicePtrsToSlice(blocks).([]common.Block), tracerr.Wrap(err)
 }
 
-// GetBlocks retrieve blocks from the DB, given a range of block numbers defined by from and to
+// getBlocks retrieve blocks from the DB, given a range of block numbers defined by from and to
-func (hdb *HistoryDB) GetBlocks(from, to int64) ([]common.Block, error) {
+func (hdb *HistoryDB) getBlocks(from, to int64) ([]common.Block, error) {
 	var blocks []*common.Block
 	err := meddler.QueryAll(
 		hdb.db, &blocks,
@@ -166,116 +164,6 @@ func (hdb *HistoryDB) addBatches(d meddler.DB, batches []common.Batch) error {
 	return nil
 }
 
-// GetBatchAPI return the batch with the given batchNum
-func (hdb *HistoryDB) GetBatchAPI(batchNum common.BatchNum) (*BatchAPI, error) {
-	batch := &BatchAPI{}
-	return batch, tracerr.Wrap(meddler.QueryRow(
-		hdb.db, 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,
-		block.timestamp, block.hash,
-	    COALESCE ((SELECT COUNT(*) FROM tx WHERE batch_num = batch.batch_num), 0) AS forged_txs
-	    FROM batch INNER JOIN block ON batch.eth_block_num = block.eth_block_num
-	 	WHERE batch_num = $1;`, batchNum,
-	))
-}
-
-// GetBatchesAPI return the batches applying the given filters
-func (hdb *HistoryDB) GetBatchesAPI(
-	minBatchNum, maxBatchNum, slotNum *uint,
-	forgerAddr *ethCommon.Address,
-	fromItem, limit *uint, order string,
-) ([]BatchAPI, uint64, error) {
-	var query string
-	var args []interface{}
-	queryStr := `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,
-	block.timestamp, block.hash,
-	COALESCE ((SELECT COUNT(*) FROM tx WHERE batch_num = batch.batch_num), 0) AS forged_txs,
-	count(*) OVER() AS total_items
-	FROM batch INNER JOIN block ON batch.eth_block_num = block.eth_block_num `
-	// Apply filters
-	nextIsAnd := false
-	// minBatchNum filter
-	if minBatchNum != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "batch.batch_num > ? "
-		args = append(args, minBatchNum)
-		nextIsAnd = true
-	}
-	// maxBatchNum filter
-	if maxBatchNum != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "batch.batch_num < ? "
-		args = append(args, maxBatchNum)
-		nextIsAnd = true
-	}
-	// slotNum filter
-	if slotNum != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "batch.slot_num = ? "
-		args = append(args, slotNum)
-		nextIsAnd = true
-	}
-	// forgerAddr filter
-	if forgerAddr != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "batch.forger_addr = ? "
-		args = append(args, forgerAddr)
-		nextIsAnd = true
-	}
-	// pagination
-	if fromItem != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		if order == OrderAsc {
-			queryStr += "batch.item_id >= ? "
-		} else {
-			queryStr += "batch.item_id <= ? "
-		}
-		args = append(args, fromItem)
-	}
-	queryStr += "ORDER BY batch.item_id "
-	if order == OrderAsc {
-		queryStr += " ASC "
-	} else {
-		queryStr += " DESC "
-	}
-	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query = hdb.db.Rebind(queryStr)
-	// log.Debug(query)
-	batchPtrs := []*BatchAPI{}
-	if err := meddler.QueryAll(hdb.db, &batchPtrs, query, args...); err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	batches := db.SlicePtrsToSlice(batchPtrs).([]BatchAPI)
-	if len(batches) == 0 {
-		return batches, 0, nil
-	}
-	return batches, batches[0].TotalItems - uint64(len(batches)), nil
-}
-
 // GetAllBatches retrieve all batches from the DB
 func (hdb *HistoryDB) GetAllBatches() ([]common.Batch, error) {
 	var batches []*common.Batch
@@ -375,22 +263,6 @@ func (hdb *HistoryDB) GetAllBids() ([]common.Bid, error) {
 	return db.SlicePtrsToSlice(bids).([]common.Bid), tracerr.Wrap(err)
 }
 
-// GetBestBidAPI returns the best bid in specific slot by slotNum
-func (hdb *HistoryDB) GetBestBidAPI(slotNum *int64) (BidAPI, error) {
-	bid := &BidAPI{}
-	err := meddler.QueryRow(
-		hdb.db, 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
-			GROUP BY bidder_addr
-		) c ON bid.bidder_addr = c.bidder_addr 
-		INNER JOIN coordinator ON c.item_id = coordinator.item_id 
-		WHERE slot_num = $1 ORDER BY item_id DESC LIMIT 1;`, slotNum,
-	)
-	return *bid, tracerr.Wrap(err)
-}
-
 // GetBestBidCoordinator returns the forger address of the highest bidder in a slot by slotNum
 func (hdb *HistoryDB) GetBestBidCoordinator(slotNum int64) (*common.BidCoordinator, error) {
 	bidCoord := &common.BidCoordinator{}
@@ -416,133 +288,6 @@ func (hdb *HistoryDB) GetBestBidCoordinator(slotNum int64) (*common.BidCoordinat
 	return bidCoord, tracerr.Wrap(err)
 }
 
-// GetBestBidsAPI returns the best bid in specific slot by slotNum
-func (hdb *HistoryDB) GetBestBidsAPI(
-	minSlotNum, maxSlotNum *int64,
-	bidderAddr *ethCommon.Address,
-	limit *uint, order string,
-) ([]BidAPI, uint64, error) {
-	var query string
-	var args []interface{}
-	// JOIN the best bid of each slot with the latest update of each coordinator
-	queryStr := `SELECT b.*, block.timestamp, coordinator.forger_addr, coordinator.url, 
-	COUNT(*) OVER() AS total_items FROM (
-	   SELECT slot_num, MAX(item_id) as maxitem 
-	   FROM bid GROUP BY slot_num
-	)
-	AS x INNER JOIN bid AS b ON b.item_id = x.maxitem
-	INNER JOIN block ON b.eth_block_num = block.eth_block_num
-	INNER JOIN (
-		SELECT bidder_addr, MAX(item_id) AS item_id FROM coordinator
-		GROUP BY bidder_addr
-	) c ON b.bidder_addr = c.bidder_addr 
-	INNER JOIN coordinator ON c.item_id = coordinator.item_id 
-	WHERE (b.slot_num >= ? AND b.slot_num <= ?)`
-	args = append(args, minSlotNum)
-	args = append(args, maxSlotNum)
-	// Apply filters
-	if bidderAddr != nil {
-		queryStr += " AND b.bidder_addr = ? "
-		args = append(args, bidderAddr)
-	}
-	queryStr += " ORDER BY b.slot_num "
-	if order == OrderAsc {
-		queryStr += "ASC "
-	} else {
-		queryStr += "DESC "
-	}
-	if limit != nil {
-		queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	}
-	query = hdb.db.Rebind(queryStr)
-	bidPtrs := []*BidAPI{}
-	if err := meddler.QueryAll(hdb.db, &bidPtrs, query, args...); err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	// log.Debug(query)
-	bids := db.SlicePtrsToSlice(bidPtrs).([]BidAPI)
-	if len(bids) == 0 {
-		return bids, 0, nil
-	}
-	return bids, bids[0].TotalItems - uint64(len(bids)), nil
-}
-
-// GetBidsAPI return the bids applying the given filters
-func (hdb *HistoryDB) GetBidsAPI(
-	slotNum *int64, bidderAddr *ethCommon.Address,
-	fromItem, limit *uint, order string,
-) ([]BidAPI, uint64, error) {
-	var query string
-	var args []interface{}
-	// JOIN each bid with the latest update of each coordinator
-	queryStr := `SELECT bid.*, block.timestamp, coord.forger_addr, coord.url, 
-	COUNT(*) OVER() AS total_items
-	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
-		GROUP BY bidder_addr
-	) c ON bid.bidder_addr = c.bidder_addr 
-	INNER JOIN coordinator coord ON c.item_id = coord.item_id `
-	// Apply filters
-	nextIsAnd := false
-	// slotNum filter
-	if slotNum != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "bid.slot_num = ? "
-		args = append(args, slotNum)
-		nextIsAnd = true
-	}
-	// bidder filter
-	if bidderAddr != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "bid.bidder_addr = ? "
-		args = append(args, bidderAddr)
-		nextIsAnd = true
-	}
-	if fromItem != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		if order == OrderAsc {
-			queryStr += "bid.item_id >= ? "
-		} else {
-			queryStr += "bid.item_id <= ? "
-		}
-		args = append(args, fromItem)
-	}
-	// pagination
-	queryStr += "ORDER BY bid.item_id "
-	if order == OrderAsc {
-		queryStr += "ASC "
-	} else {
-		queryStr += "DESC "
-	}
-	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query, argsQ, err := sqlx.In(queryStr, args...)
-	if err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	query = hdb.db.Rebind(query)
-	bids := []*BidAPI{}
-	if err := meddler.QueryAll(hdb.db, &bids, query, argsQ...); err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	if len(bids) == 0 {
-		return []BidAPI{}, 0, nil
-	}
-	return db.SlicePtrsToSlice(bids).([]BidAPI), bids[0].TotalItems - uint64(len(bids)), nil
-}
-
 // AddCoordinators insert Coordinators into the DB
 func (hdb *HistoryDB) AddCoordinators(coordinators []common.Coordinator) error {
 	return tracerr.Wrap(hdb.addCoordinators(hdb.db, coordinators))
@@ -708,77 +453,6 @@ func (hdb *HistoryDB) GetAllTokens() ([]TokenWithUSD, error) {
 	return db.SlicePtrsToSlice(tokens).([]TokenWithUSD), tracerr.Wrap(err)
 }
 
-// GetTokens returns a list of tokens from the DB
-func (hdb *HistoryDB) GetTokens(
-	ids []common.TokenID, symbols []string, name string, fromItem,
-	limit *uint, order string,
-) ([]TokenWithUSD, uint64, error) {
-	var query string
-	var args []interface{}
-	queryStr := `SELECT * , COUNT(*) OVER() AS total_items FROM token `
-	// Apply filters
-	nextIsAnd := false
-	if len(ids) > 0 {
-		queryStr += "WHERE token_id IN (?) "
-		nextIsAnd = true
-		args = append(args, ids)
-	}
-	if len(symbols) > 0 {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "symbol IN (?) "
-		args = append(args, symbols)
-		nextIsAnd = true
-	}
-	if name != "" {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "name ~ ? "
-		args = append(args, name)
-		nextIsAnd = true
-	}
-	if fromItem != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		if order == OrderAsc {
-			queryStr += "item_id >= ? "
-		} else {
-			queryStr += "item_id <= ? "
-		}
-		args = append(args, fromItem)
-	}
-	// pagination
-	queryStr += "ORDER BY item_id "
-	if order == OrderAsc {
-		queryStr += "ASC "
-	} else {
-		queryStr += "DESC "
-	}
-	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query, argsQ, err := sqlx.In(queryStr, args...)
-	if err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	query = hdb.db.Rebind(query)
-	tokens := []*TokenWithUSD{}
-	if err := meddler.QueryAll(hdb.db, &tokens, query, argsQ...); err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	if len(tokens) == 0 {
-		return []TokenWithUSD{}, 0, nil
-	}
-	return db.SlicePtrsToSlice(tokens).([]TokenWithUSD), uint64(len(tokens)) - tokens[0].TotalItems, nil
-}
-
 // GetTokenSymbols returns all the token symbols from the DB
 func (hdb *HistoryDB) GetTokenSymbols() ([]string, error) {
 	var tokenSymbols []string
@@ -951,153 +625,6 @@ func (hdb *HistoryDB) addTxs(d meddler.DB, txs []txWrite) error {
 	))
 }
 
-// GetHistoryTx returns a tx from the DB given a TxID
-func (hdb *HistoryDB) GetHistoryTx(txID common.TxID) (*TxAPI, error) {
-	// Warning: amount_success and deposit_amount_success have true as default for
-	// performance reasons. The expected default value is false (when txs are unforged)
-	// this case is handled at the function func (tx TxAPI) MarshalJSON() ([]byte, error)
-	tx := &TxAPI{}
-	err := meddler.QueryRow(
-		hdb.db, 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, 
-		tx.batch_num, tx.eth_block_num, tx.to_forge_l1_txs_num, tx.user_origin, 
-		tx.deposit_amount, tx.deposit_amount_usd, tx.deposit_amount_success, tx.fee, tx.fee_usd, tx.nonce,
-		token.token_id, token.item_id AS token_item_id, token.eth_block_num AS token_block,
-		token.eth_addr, token.name, token.symbol, token.decimals, token.usd,
-		token.usd_update, block.timestamp
-		FROM tx INNER JOIN token ON tx.token_id = token.token_id 
-		INNER JOIN block ON tx.eth_block_num = block.eth_block_num 
-		WHERE tx.id = $1;`, txID,
-	)
-	return tx, tracerr.Wrap(err)
-}
-
-// GetHistoryTxs returns a list of txs from the DB using the HistoryTx struct
-// and pagination info
-func (hdb *HistoryDB) GetHistoryTxs(
-	ethAddr *ethCommon.Address, bjj *babyjub.PublicKeyComp,
-	tokenID *common.TokenID, idx *common.Idx, batchNum *uint, txType *common.TxType,
-	fromItem, limit *uint, order string,
-) ([]TxAPI, uint64, error) {
-	// Warning: amount_success and deposit_amount_success have true as default for
-	// performance reasons. The expected default value is false (when txs are unforged)
-	// this case is handled at the function func (tx TxAPI) MarshalJSON() ([]byte, error)
-	if ethAddr != nil && bjj != nil {
-		return nil, 0, tracerr.Wrap(errors.New("ethAddr and bjj are incompatible"))
-	}
-	var query string
-	var args []interface{}
-	queryStr := `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, 
-	tx.batch_num, tx.eth_block_num, tx.to_forge_l1_txs_num, tx.user_origin, 
-	tx.deposit_amount, tx.deposit_amount_usd, tx.deposit_amount_success, tx.fee, tx.fee_usd, tx.nonce,
-	token.token_id, token.item_id AS token_item_id, token.eth_block_num AS token_block,
-	token.eth_addr, token.name, token.symbol, token.decimals, token.usd,
-	token.usd_update, block.timestamp, count(*) OVER() AS total_items 
-	FROM tx INNER JOIN token ON tx.token_id = token.token_id 
-	INNER JOIN block ON tx.eth_block_num = block.eth_block_num `
-	// Apply filters
-	nextIsAnd := false
-	// ethAddr filter
-	if ethAddr != nil {
-		queryStr += "WHERE (tx.from_eth_addr = ? OR tx.to_eth_addr = ?) "
-		nextIsAnd = true
-		args = append(args, ethAddr, ethAddr)
-	} else if bjj != nil { // bjj filter
-		queryStr += "WHERE (tx.from_bjj = ? OR tx.to_bjj = ?) "
-		nextIsAnd = true
-		args = append(args, bjj, bjj)
-	}
-	// tokenID filter
-	if tokenID != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "tx.token_id = ? "
-		args = append(args, tokenID)
-		nextIsAnd = true
-	}
-	// idx filter
-	if idx != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "(tx.effective_from_idx = ? OR tx.to_idx = ?) "
-		args = append(args, idx, idx)
-		nextIsAnd = true
-	}
-	// batchNum filter
-	if batchNum != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "tx.batch_num = ? "
-		args = append(args, batchNum)
-		nextIsAnd = true
-	}
-	// txType filter
-	if txType != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "tx.type = ? "
-		args = append(args, txType)
-		nextIsAnd = true
-	}
-	if fromItem != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		if order == OrderAsc {
-			queryStr += "tx.item_id >= ? "
-		} else {
-			queryStr += "tx.item_id <= ? "
-		}
-		args = append(args, fromItem)
-		nextIsAnd = true
-	}
-	if nextIsAnd {
-		queryStr += "AND "
-	} else {
-		queryStr += "WHERE "
-	}
-	queryStr += "tx.batch_num IS NOT NULL "
-
-	// pagination
-	queryStr += "ORDER BY tx.item_id "
-	if order == OrderAsc {
-		queryStr += " ASC "
-	} else {
-		queryStr += " DESC "
-	}
-	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query = hdb.db.Rebind(queryStr)
-	// log.Debug(query)
-	txsPtrs := []*TxAPI{}
-	if err := meddler.QueryAll(hdb.db, &txsPtrs, query, args...); err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	txs := db.SlicePtrsToSlice(txsPtrs).([]TxAPI)
-	if len(txs) == 0 {
-		return txs, 0, nil
-	}
-	return txs, txs[0].TotalItems - uint64(len(txs)), nil
-}
-
 // GetAllExits returns all exit from the DB
 func (hdb *HistoryDB) GetAllExits() ([]common.ExitInfo, error) {
 	var exits []*common.ExitInfo
@@ -1110,137 +637,6 @@ func (hdb *HistoryDB) GetAllExits() ([]common.ExitInfo, error) {
 	return db.SlicePtrsToSlice(exits).([]common.ExitInfo), tracerr.Wrap(err)
 }
 
-// GetExitAPI returns a exit from the DB
-func (hdb *HistoryDB) GetExitAPI(batchNum *uint, idx *common.Idx) (*ExitAPI, error) {
-	exit := &ExitAPI{}
-	err := meddler.QueryRow(
-		hdb.db, 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,
-		exit_tree.delayed_withdraw_request, exit_tree.delayed_withdrawn,
-		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, token.usd_update
-		FROM exit_tree INNER JOIN account ON exit_tree.account_idx = account.idx 
-		INNER JOIN token ON account.token_id = token.token_id 
-		WHERE exit_tree.batch_num = $1 AND exit_tree.account_idx = $2;`, batchNum, idx,
-	)
-	return exit, tracerr.Wrap(err)
-}
-
-// GetExitsAPI returns a list of exits from the DB and pagination info
-func (hdb *HistoryDB) GetExitsAPI(
-	ethAddr *ethCommon.Address, bjj *babyjub.PublicKeyComp, tokenID *common.TokenID,
-	idx *common.Idx, batchNum *uint, onlyPendingWithdraws *bool,
-	fromItem, limit *uint, order string,
-) ([]ExitAPI, uint64, error) {
-	if ethAddr != nil && bjj != nil {
-		return nil, 0, tracerr.Wrap(errors.New("ethAddr and bjj are incompatible"))
-	}
-	var query string
-	var args []interface{}
-	queryStr := `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,
-	exit_tree.delayed_withdraw_request, exit_tree.delayed_withdrawn,
-	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, token.usd_update, COUNT(*) OVER() AS total_items
-	FROM exit_tree INNER JOIN account ON exit_tree.account_idx = account.idx 
-	INNER JOIN token ON account.token_id = token.token_id `
-	// Apply filters
-	nextIsAnd := false
-	// ethAddr filter
-	if ethAddr != nil {
-		queryStr += "WHERE account.eth_addr = ? "
-		nextIsAnd = true
-		args = append(args, ethAddr)
-	} else if bjj != nil { // bjj filter
-		queryStr += "WHERE account.bjj = ? "
-		nextIsAnd = true
-		args = append(args, bjj)
-	}
-	// tokenID filter
-	if tokenID != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "account.token_id = ? "
-		args = append(args, tokenID)
-		nextIsAnd = true
-	}
-	// idx filter
-	if idx != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "exit_tree.account_idx = ? "
-		args = append(args, idx)
-		nextIsAnd = true
-	}
-	// batchNum filter
-	if batchNum != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "exit_tree.batch_num = ? "
-		args = append(args, batchNum)
-		nextIsAnd = true
-	}
-	// onlyPendingWithdraws
-	if onlyPendingWithdraws != nil {
-		if *onlyPendingWithdraws {
-			if nextIsAnd {
-				queryStr += "AND "
-			} else {
-				queryStr += "WHERE "
-			}
-			queryStr += "(exit_tree.instant_withdrawn IS NULL AND exit_tree.delayed_withdrawn IS NULL) "
-			nextIsAnd = true
-		}
-	}
-	if fromItem != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		if order == OrderAsc {
-			queryStr += "exit_tree.item_id >= ? "
-		} else {
-			queryStr += "exit_tree.item_id <= ? "
-		}
-		args = append(args, fromItem)
-		// nextIsAnd = true
-	}
-	// pagination
-	queryStr += "ORDER BY exit_tree.item_id "
-	if order == OrderAsc {
-		queryStr += " ASC "
-	} else {
-		queryStr += " DESC "
-	}
-	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query = hdb.db.Rebind(queryStr)
-	// log.Debug(query)
-	exits := []*ExitAPI{}
-	if err := meddler.QueryAll(hdb.db, &exits, query, args...); err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	if len(exits) == 0 {
-		return []ExitAPI{}, 0, nil
-	}
-	return db.SlicePtrsToSlice(exits).([]ExitAPI), exits[0].TotalItems - uint64(len(exits)), nil
-}
-
 // GetAllL1UserTxs returns all L1UserTxs from the DB
 func (hdb *HistoryDB) GetAllL1UserTxs() ([]common.L1Tx, error) {
 	var txs []*common.L1Tx
@@ -1381,19 +777,6 @@ func (hdb *HistoryDB) GetAllBucketUpdates() ([]common.BucketUpdate, error) {
 	return db.SlicePtrsToSlice(bucketUpdates).([]common.BucketUpdate), tracerr.Wrap(err)
 }
 
-// GetBucketUpdates retrieves latest values for each bucket
-func (hdb *HistoryDB) GetBucketUpdates() ([]BucketUpdateAPI, error) {
-	var bucketUpdates []*BucketUpdateAPI
-	err := meddler.QueryAll(
-		hdb.db, &bucketUpdates,
-		`SELECT num_bucket, withdrawals FROM bucket_update 
-		WHERE item_id in(SELECT max(item_id) FROM bucket_update 
-		group by num_bucket) 
-		ORDER BY num_bucket ASC;`,
-	)
-	return db.SlicePtrsToSlice(bucketUpdates).([]BucketUpdateAPI), tracerr.Wrap(err)
-}
-
 func (hdb *HistoryDB) addTokenExchanges(d meddler.DB, tokenExchanges []common.TokenExchange) error {
 	if len(tokenExchanges) == 0 {
 		return nil
@@ -1698,274 +1081,22 @@ func (hdb *HistoryDB) GetCoordinatorAPI(bidderAddr ethCommon.Address) (*Coordina
 	return coordinator, tracerr.Wrap(err)
 }
 
-// GetCoordinatorsAPI returns a list of coordinators from the DB and pagination info
-func (hdb *HistoryDB) GetCoordinatorsAPI(
-	bidderAddr, forgerAddr *ethCommon.Address,
-	fromItem, limit *uint, order string,
-) ([]CoordinatorAPI, uint64, error) {
-	var query string
-	var args []interface{}
-	queryStr := `SELECT coordinator.*, COUNT(*) OVER() AS total_items
-	FROM coordinator INNER JOIN (
-		SELECT MAX(item_id) AS item_id FROM coordinator
-		GROUP BY bidder_addr
-	) c ON coordinator.item_id = c.item_id `
-	// Apply filters
-	nextIsAnd := false
-	if bidderAddr != nil {
-		queryStr += "WHERE bidder_addr = ? "
-		nextIsAnd = true
-		args = append(args, bidderAddr)
-	}
-	if forgerAddr != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "forger_addr = ? "
-		nextIsAnd = true
-		args = append(args, forgerAddr)
-	}
-	if fromItem != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		if order == OrderAsc {
-			queryStr += "coordinator.item_id >= ? "
-		} else {
-			queryStr += "coordinator.item_id <= ? "
-		}
-		args = append(args, fromItem)
-	}
-	// pagination
-	queryStr += "ORDER BY coordinator.item_id "
-	if order == OrderAsc {
-		queryStr += " ASC "
-	} else {
-		queryStr += " DESC "
-	}
-	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query = hdb.db.Rebind(queryStr)
-
-	coordinators := []*CoordinatorAPI{}
-	if err := meddler.QueryAll(hdb.db, &coordinators, query, args...); err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	if len(coordinators) == 0 {
-		return []CoordinatorAPI{}, 0, nil
-	}
-	return db.SlicePtrsToSlice(coordinators).([]CoordinatorAPI),
-		coordinators[0].TotalItems - uint64(len(coordinators)), nil
-}
-
 // 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))
 }
 
-// GetAuctionVars returns auction variables
+// GetTokensTest used to get tokens in a testing context
-func (hdb *HistoryDB) GetAuctionVars() (*common.AuctionVariables, error) {
+func (hdb *HistoryDB) GetTokensTest() ([]TokenWithUSD, error) {
-	auctionVars := &common.AuctionVariables{}
+	tokens := []*TokenWithUSD{}
-	err := meddler.QueryRow(
+	if err := meddler.QueryAll(
-		hdb.db, auctionVars, `SELECT * FROM auction_vars;`,
+		hdb.db, &tokens,
-	)
+		"SELECT * FROM TOKEN",
-	return auctionVars, tracerr.Wrap(err)
+	); err != nil {
-}
-
-// GetAuctionVarsUntilSetSlotNum returns all the updates of the auction vars
-// from the last entry in which DefaultSlotSetBidSlotNum <= slotNum
-func (hdb *HistoryDB) GetAuctionVarsUntilSetSlotNum(slotNum int64, maxItems int) ([]MinBidInfo, error) {
-	auctionVars := []*MinBidInfo{}
-	query := `
-		SELECT DISTINCT default_slot_set_bid, default_slot_set_bid_slot_num FROM auction_vars
-		WHERE default_slot_set_bid_slot_num < $1
-		ORDER BY default_slot_set_bid_slot_num DESC
-		LIMIT $2;
-	`
-	err := meddler.QueryAll(hdb.db, &auctionVars, query, slotNum, maxItems)
-	if err != nil {
 		return nil, tracerr.Wrap(err)
 	}
-	return db.SlicePtrsToSlice(auctionVars).([]MinBidInfo), nil
+	if len(tokens) == 0 {
-}
+		return []TokenWithUSD{}, nil
-
+	}
-// GetAccountAPI returns an account by its index
+	return db.SlicePtrsToSlice(tokens).([]TokenWithUSD), nil
-func (hdb *HistoryDB) GetAccountAPI(idx common.Idx) (*AccountAPI, error) {
-	account := &AccountAPI{}
-	err := meddler.QueryRow(hdb.db, 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, token.usd_update 
-	FROM account INNER JOIN token ON account.token_id = token.token_id WHERE idx = $1;`, idx)
-
-	if err != nil {
-		return nil, tracerr.Wrap(err)
-	}
-
-	return account, nil
-}
-
-// GetAccountsAPI returns a list of accounts from the DB and pagination info
-func (hdb *HistoryDB) GetAccountsAPI(
-	tokenIDs []common.TokenID, ethAddr *ethCommon.Address,
-	bjj *babyjub.PublicKeyComp, fromItem, limit *uint, order string,
-) ([]AccountAPI, uint64, error) {
-	if ethAddr != nil && bjj != nil {
-		return nil, 0, tracerr.Wrap(errors.New("ethAddr and bjj are incompatible"))
-	}
-	var query string
-	var args []interface{}
-	queryStr := `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, token.usd_update, 
-	COUNT(*) OVER() AS total_items
-	FROM account INNER JOIN token ON account.token_id = token.token_id `
-	// Apply filters
-	nextIsAnd := false
-	// ethAddr filter
-	if ethAddr != nil {
-		queryStr += "WHERE account.eth_addr = ? "
-		nextIsAnd = true
-		args = append(args, ethAddr)
-	} else if bjj != nil { // bjj filter
-		queryStr += "WHERE account.bjj = ? "
-		nextIsAnd = true
-		args = append(args, bjj)
-	}
-	// tokenID filter
-	if len(tokenIDs) > 0 {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		queryStr += "account.token_id IN (?) "
-		args = append(args, tokenIDs)
-		nextIsAnd = true
-	}
-	if fromItem != nil {
-		if nextIsAnd {
-			queryStr += "AND "
-		} else {
-			queryStr += "WHERE "
-		}
-		if order == OrderAsc {
-			queryStr += "account.item_id >= ? "
-		} else {
-			queryStr += "account.item_id <= ? "
-		}
-		args = append(args, fromItem)
-	}
-	// pagination
-	queryStr += "ORDER BY account.item_id "
-	if order == OrderAsc {
-		queryStr += " ASC "
-	} else {
-		queryStr += " DESC "
-	}
-	queryStr += fmt.Sprintf("LIMIT %d;", *limit)
-	query, argsQ, err := sqlx.In(queryStr, args...)
-	if err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	query = hdb.db.Rebind(query)
-
-	accounts := []*AccountAPI{}
-	if err := meddler.QueryAll(hdb.db, &accounts, query, argsQ...); err != nil {
-		return nil, 0, tracerr.Wrap(err)
-	}
-	if len(accounts) == 0 {
-		return []AccountAPI{}, 0, nil
-	}
-
-	return db.SlicePtrsToSlice(accounts).([]AccountAPI),
-		accounts[0].TotalItems - uint64(len(accounts)), nil
-}
-
-// GetMetrics returns metrics
-func (hdb *HistoryDB) GetMetrics(lastBatchNum common.BatchNum) (*Metrics, error) {
-	metricsTotals := &MetricsTotals{}
-	metrics := &Metrics{}
-	err := meddler.QueryRow(
-		hdb.db, 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
-		WHERE block.timestamp >= NOW() - INTERVAL '24 HOURS';`)
-	if err != nil {
-		return nil, tracerr.Wrap(err)
-	}
-
-	seconds := metricsTotals.MaxTimestamp.Sub(metricsTotals.MinTimestamp).Seconds()
-	// Avoid dividing by 0
-	if seconds == 0 {
-		seconds++
-	}
-
-	metrics.TransactionsPerSecond = float64(metricsTotals.TotalTransactions) / seconds
-
-	if (lastBatchNum - metricsTotals.FirstBatchNum) > 0 {
-		metrics.TransactionsPerBatch = float64(metricsTotals.TotalTransactions) /
-			float64(lastBatchNum-metricsTotals.FirstBatchNum+1)
-	} else {
-		metrics.TransactionsPerBatch = float64(0)
-	}
-
-	err = meddler.QueryRow(
-		hdb.db, 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 {
-		return nil, tracerr.Wrap(err)
-	}
-	if metricsTotals.TotalBatches > 0 {
-		metrics.BatchFrequency = seconds / float64(metricsTotals.TotalBatches)
-	} else {
-		metrics.BatchFrequency = 0
-	}
-	if metricsTotals.TotalTransactions > 0 {
-		metrics.AvgTransactionFee = metricsTotals.TotalFeesUSD / float64(metricsTotals.TotalTransactions)
-	} else {
-		metrics.AvgTransactionFee = 0
-	}
-	err = meddler.QueryRow(
-		hdb.db, metrics,
-		`SELECT COUNT(*) AS total_bjjs, COUNT(DISTINCT(bjj)) AS total_accounts FROM account;`)
-	if err != nil {
-		return nil, tracerr.Wrap(err)
-	}
-
-	return metrics, nil
-}
-
-// GetAvgTxFee returns average transaction fee of the last 1h
-func (hdb *HistoryDB) GetAvgTxFee() (float64, error) {
-	metricsTotals := &MetricsTotals{}
-	err := meddler.QueryRow(
-		hdb.db, 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';`)
-	if err != nil {
-		return 0, tracerr.Wrap(err)
-	}
-	err = meddler.QueryRow(
-		hdb.db, 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 {
-		return 0, tracerr.Wrap(err)
-	}
-
-	var avgTransactionFee float64
-	if metricsTotals.TotalTransactions > 0 {
-		avgTransactionFee = metricsTotals.TotalFeesUSD / float64(metricsTotals.TotalTransactions)
-	} else {
-		avgTransactionFee = 0
-	}
-
-	return avgTransactionFee, nil
 }

db/historydb/historydb_test.go

@@ -22,6 +22,7 @@ import (
 )
 
 var historyDB *HistoryDB
+var historyDBWithACC *HistoryDB
 
 // In order to run the test you need to run a Posgres DB with
 // a database named "history" that is accessible by
@@ -38,10 +39,12 @@ func TestMain(m *testing.M) {
 	if err != nil {
 		panic(err)
 	}
-	historyDB = NewHistoryDB(db)
+	historyDB = NewHistoryDB(db, nil)
 	if err != nil {
 		panic(err)
 	}
+	apiConnCon := dbUtils.NewAPICnnectionController(1, time.Second)
+	historyDBWithACC = NewHistoryDB(db, apiConnCon)
 	// Run tests
 	result := m.Run()
 	// Close DB
@@ -85,7 +88,7 @@ func TestBlocks(t *testing.T) {
 		blocks...,
 	)
 	// Get all blocks from DB
-	fetchedBlocks, err := historyDB.GetBlocks(fromBlock, toBlock)
+	fetchedBlocks, err := historyDB.getBlocks(fromBlock, toBlock)
 	assert.Equal(t, len(blocks), len(fetchedBlocks))
 	// Compare generated vs getted blocks
 	assert.NoError(t, err)
@@ -245,9 +248,8 @@ func TestTokens(t *testing.T) {
 	err := historyDB.AddTokens(tokens)
 	assert.NoError(t, err)
 	tokens = append([]common.Token{ethToken}, tokens...)
-	limit := uint(10)
 	// Fetch tokens
-	fetchedTokens, _, err := historyDB.GetTokens(nil, nil, "", nil, &limit, OrderAsc)
+	fetchedTokens, err := historyDB.GetTokensTest()
 	assert.NoError(t, err)
 	// Compare fetched tokens vs generated tokens
 	// All the tokens should have USDUpdate setted by the DB trigger
@@ -267,7 +269,7 @@ func TestTokens(t *testing.T) {
 		assert.NoError(t, historyDB.UpdateTokenValue(token.Symbol, value))
 	}
 	// Fetch tokens
-	fetchedTokens, _, err = historyDB.GetTokens(nil, nil, "", nil, &limit, OrderAsc)
+	fetchedTokens, err = historyDB.GetTokensTest()
 	assert.NoError(t, err)
 	// Compare fetched tokens vs generated tokens
 	// All the tokens should have USDUpdate setted by the DB trigger
@@ -302,9 +304,8 @@ func TestTokensUTF8(t *testing.T) {
 	assert.NoError(t, err)
 	// Work with nonUTFTokens as tokens one gets updated and non UTF-8 characters are lost
 	nonUTFTokens = append([]common.Token{ethToken}, nonUTFTokens...)
-	limit := uint(10)
 	// Fetch tokens
-	fetchedTokens, _, err := historyDB.GetTokens(nil, nil, "", nil, &limit, OrderAsc)
+	fetchedTokens, err := historyDB.GetTokensTest()
 	assert.NoError(t, err)
 	// Compare fetched tokens vs generated tokens
 	// All the tokens should have USDUpdate setted by the DB trigger
@@ -324,7 +325,7 @@ func TestTokensUTF8(t *testing.T) {
 		assert.NoError(t, historyDB.UpdateTokenValue(token.Symbol, value))
 	}
 	// Fetch tokens
-	fetchedTokens, _, err = historyDB.GetTokens(nil, nil, "", nil, &limit, OrderAsc)
+	fetchedTokens, err = historyDB.GetTokensTest()
 	assert.NoError(t, err)
 	// Compare fetched tokens vs generated tokens
 	// All the tokens should have USDUpdate setted by the DB trigger
@@ -1087,9 +1088,8 @@ func TestAddEscapeHatchWithdrawals(t *testing.T) {
 	assert.Equal(t, escapeHatchWithdrawals, dbEscapeHatchWithdrawals)
 }
 
-func TestGetMetrics(t *testing.T) {
+func TestGetMetricsAPI(t *testing.T) {
 	test.WipeDB(historyDB.DB())
-
 	set := `
 		Type: Blockchain
 
@@ -1146,7 +1146,7 @@ func TestGetMetrics(t *testing.T) {
 		assert.NoError(t, err)
 	}
 
-	res, err := historyDB.GetMetrics(common.BatchNum(numBatches))
+	res, err := historyDBWithACC.GetMetricsAPI(common.BatchNum(numBatches))
 	assert.NoError(t, err)
 
 	assert.Equal(t, float64(numTx)/float64(numBatches-1), res.TransactionsPerBatch)
@@ -1165,7 +1165,7 @@ func TestGetMetrics(t *testing.T) {
 	assert.Equal(t, float64(0), res.AvgTransactionFee)
 }
 
-func TestGetMetricsMoreThan24Hours(t *testing.T) {
+func TestGetMetricsAPIMoreThan24Hours(t *testing.T) {
 	test.WipeDB(historyDB.DB())
 
 	testUsersLen := 3
@@ -1226,7 +1226,7 @@ func TestGetMetricsMoreThan24Hours(t *testing.T) {
 		assert.NoError(t, err)
 	}
 
-	res, err := historyDB.GetMetrics(common.BatchNum(numBatches))
+	res, err := historyDBWithACC.GetMetricsAPI(common.BatchNum(numBatches))
 	assert.NoError(t, err)
 
 	assert.Equal(t, math.Trunc((float64(numTx)/float64(numBatches-1))/0.001)*0.001, math.Trunc(res.TransactionsPerBatch/0.001)*0.001)
@@ -1245,15 +1245,15 @@ func TestGetMetricsMoreThan24Hours(t *testing.T) {
 	assert.Equal(t, float64(0), res.AvgTransactionFee)
 }
 
-func TestGetMetricsEmpty(t *testing.T) {
+func TestGetMetricsAPIEmpty(t *testing.T) {
 	test.WipeDB(historyDB.DB())
-	_, err := historyDB.GetMetrics(0)
+	_, err := historyDBWithACC.GetMetricsAPI(0)
 	assert.NoError(t, err)
 }
 
 func TestGetAvgTxFeeEmpty(t *testing.T) {
 	test.WipeDB(historyDB.DB())
-	_, err := historyDB.GetAvgTxFee()
+	_, err := historyDBWithACC.GetAvgTxFeeAPI()
 	assert.NoError(t, err)
 }
 

db/l2db/apiqueries.go

@@ -0,0 +1,85 @@
+package l2db
+
+import (
+	ethCommon "github.com/ethereum/go-ethereum/common"
+	"github.com/hermeznetwork/hermez-node/common"
+	"github.com/hermeznetwork/tracerr"
+	"github.com/russross/meddler"
+)
+
+// AddAccountCreationAuthAPI inserts an account creation authorization into the DB
+func (l2db *L2DB) AddAccountCreationAuthAPI(auth *common.AccountCreationAuth) error {
+	cancel, err := l2db.apiConnCon.Acquire()
+	defer cancel()
+	if err != nil {
+		return tracerr.Wrap(err)
+	}
+	defer l2db.apiConnCon.Release()
+	return l2db.AddAccountCreationAuth(auth)
+}
+
+// GetAccountCreationAuthAPI returns an account creation authorization from the DB
+func (l2db *L2DB) GetAccountCreationAuthAPI(addr ethCommon.Address) (*AccountCreationAuthAPI, error) {
+	cancel, err := l2db.apiConnCon.Acquire()
+	defer cancel()
+	if err != nil {
+		return nil, tracerr.Wrap(err)
+	}
+	defer l2db.apiConnCon.Release()
+	auth := new(AccountCreationAuthAPI)
+	return auth, tracerr.Wrap(meddler.QueryRow(
+		l2db.db, auth,
+		"SELECT * FROM account_creation_auth WHERE eth_addr = $1;",
+		addr,
+	))
+}
+
+// AddTxAPI inserts a tx to the pool
+func (l2db *L2DB) AddTxAPI(tx *PoolL2TxWrite) error {
+	cancel, err := l2db.apiConnCon.Acquire()
+	defer cancel()
+	if err != nil {
+		return tracerr.Wrap(err)
+	}
+	defer l2db.apiConnCon.Release()
+	row := l2db.db.QueryRow(
+		"SELECT COUNT(*) FROM tx_pool WHERE state = $1;",
+		common.PoolL2TxStatePending,
+	)
+	var totalTxs uint32
+	if err := row.Scan(&totalTxs); err != nil {
+		return tracerr.Wrap(err)
+	}
+	if totalTxs >= l2db.maxTxs {
+		return tracerr.New(
+			"The pool is at full capacity. More transactions are not accepted currently",
+		)
+	}
+	return tracerr.Wrap(meddler.Insert(l2db.db, "tx_pool", tx))
+}
+
+// selectPoolTxAPI select part of queries to get PoolL2TxRead
+const selectPoolTxAPI = `SELECT  tx_pool.tx_id, hez_idx(tx_pool.from_idx, token.symbol) AS from_idx, tx_pool.effective_from_eth_addr, 
+tx_pool.effective_from_bjj, hez_idx(tx_pool.to_idx, token.symbol) AS to_idx, tx_pool.effective_to_eth_addr, 
+tx_pool.effective_to_bjj, tx_pool.token_id, tx_pool.amount, tx_pool.fee, tx_pool.nonce, 
+tx_pool.state, tx_pool.info, tx_pool.signature, tx_pool.timestamp, tx_pool.batch_num, hez_idx(tx_pool.rq_from_idx, token.symbol) AS rq_from_idx, 
+hez_idx(tx_pool.rq_to_idx, token.symbol) AS rq_to_idx, tx_pool.rq_to_eth_addr, tx_pool.rq_to_bjj, tx_pool.rq_token_id, tx_pool.rq_amount, 
+tx_pool.rq_fee, tx_pool.rq_nonce, tx_pool.tx_type, 
+token.item_id AS token_item_id, token.eth_block_num, token.eth_addr, token.name, token.symbol, token.decimals, token.usd, token.usd_update 
+FROM tx_pool INNER JOIN token ON tx_pool.token_id = token.token_id `
+
+// GetTxAPI return the specified Tx in PoolTxAPI format
+func (l2db *L2DB) GetTxAPI(txID common.TxID) (*PoolTxAPI, error) {
+	cancel, err := l2db.apiConnCon.Acquire()
+	defer cancel()
+	if err != nil {
+		return nil, tracerr.Wrap(err)
+	}
+	defer l2db.apiConnCon.Release()
+	tx := new(PoolTxAPI)
+	return tx, tracerr.Wrap(meddler.QueryRow(
+		l2db.db, tx,
+		selectPoolTxAPI+"WHERE tx_id = $1;",
+		txID,
+	))
+}

db/l2db/l2db.go

@@ -25,17 +25,25 @@ type L2DB struct {
 	safetyPeriod common.BatchNum
 	ttl          time.Duration
 	maxTxs       uint32 // limit of txs that are accepted in the pool
+	apiConnCon   *db.APIConnectionController
 }
 
 // NewL2DB creates a L2DB.
 // 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, safetyPeriod common.BatchNum, maxTxs uint32, TTL time.Duration) *L2DB {
+func NewL2DB(
+	db *sqlx.DB,
+	safetyPeriod common.BatchNum,
+	maxTxs uint32,
+	TTL time.Duration,
+	apiConnCon *db.APIConnectionController,
+) *L2DB {
 	return &L2DB{
 		db:           db,
 		safetyPeriod: safetyPeriod,
 		ttl:          TTL,
 		maxTxs:       maxTxs,
+		apiConnCon:   apiConnCon,
 	}
 }
 
@@ -47,7 +55,6 @@ func (l2db *L2DB) DB() *sqlx.DB {
 
 // AddAccountCreationAuth inserts an account creation authorization into the DB
 func (l2db *L2DB) AddAccountCreationAuth(auth *common.AccountCreationAuth) error {
-	// return meddler.Insert(l2db.db, "account_creation_auth", auth)
 	_, err := l2db.db.Exec(
 		`INSERT INTO account_creation_auth (eth_addr, bjj, signature)
 		VALUES ($1, $2, $3);`,
@@ -66,16 +73,6 @@ func (l2db *L2DB) GetAccountCreationAuth(addr ethCommon.Address) (*common.Accoun
 	))
 }
 
-// GetAccountCreationAuthAPI returns an account creation authorization from the DB
-func (l2db *L2DB) GetAccountCreationAuthAPI(addr ethCommon.Address) (*AccountCreationAuthAPI, error) {
-	auth := new(AccountCreationAuthAPI)
-	return auth, tracerr.Wrap(meddler.QueryRow(
-		l2db.db, auth,
-		"SELECT * FROM account_creation_auth WHERE eth_addr = $1;",
-		addr,
-	))
-}
-
 // AddTx inserts a tx to the pool
 func (l2db *L2DB) AddTx(tx *PoolL2TxWrite) error {
 	row := l2db.db.QueryRow(
@@ -173,16 +170,6 @@ func (l2db *L2DB) AddTxTest(tx *common.PoolL2Tx) error {
 	return tracerr.Wrap(meddler.Insert(l2db.db, "tx_pool", insertTx))
 }
 
-// selectPoolTxAPI select part of queries to get PoolL2TxRead
-const selectPoolTxAPI = `SELECT  tx_pool.tx_id, hez_idx(tx_pool.from_idx, token.symbol) AS from_idx, tx_pool.effective_from_eth_addr, 
-tx_pool.effective_from_bjj, hez_idx(tx_pool.to_idx, token.symbol) AS to_idx, tx_pool.effective_to_eth_addr, 
-tx_pool.effective_to_bjj, tx_pool.token_id, tx_pool.amount, tx_pool.fee, tx_pool.nonce, 
-tx_pool.state, tx_pool.info, tx_pool.signature, tx_pool.timestamp, tx_pool.batch_num, hez_idx(tx_pool.rq_from_idx, token.symbol) AS rq_from_idx, 
-hez_idx(tx_pool.rq_to_idx, token.symbol) AS rq_to_idx, tx_pool.rq_to_eth_addr, tx_pool.rq_to_bjj, tx_pool.rq_token_id, tx_pool.rq_amount, 
-tx_pool.rq_fee, tx_pool.rq_nonce, tx_pool.tx_type, 
-token.item_id AS token_item_id, token.eth_block_num, token.eth_addr, token.name, token.symbol, token.decimals, token.usd, token.usd_update 
-FROM tx_pool INNER JOIN token ON tx_pool.token_id = token.token_id `
-
 // selectPoolTxCommon select part of queries to get common.PoolL2Tx
 const selectPoolTxCommon = `SELECT  tx_pool.tx_id, from_idx, to_idx, tx_pool.to_eth_addr, 
 tx_pool.to_bjj, tx_pool.token_id, tx_pool.amount, tx_pool.fee, tx_pool.nonce, 
@@ -202,16 +189,6 @@ func (l2db *L2DB) GetTx(txID common.TxID) (*common.PoolL2Tx, error) {
 	))
 }
 
-// GetTxAPI return the specified Tx in PoolTxAPI format
-func (l2db *L2DB) GetTxAPI(txID common.TxID) (*PoolTxAPI, error) {
-	tx := new(PoolTxAPI)
-	return tx, tracerr.Wrap(meddler.QueryRow(
-		l2db.db, tx,
-		selectPoolTxAPI+"WHERE tx_id = $1;",
-		txID,
-	))
-}
-
 // GetPendingTxs return all the pending txs of the L2DB, that have a non NULL AbsoluteFee
 func (l2db *L2DB) GetPendingTxs() ([]common.PoolL2Tx, error) {
 	var txs []*common.PoolL2Tx

db/l2db/l2db_test.go

@@ -21,6 +21,7 @@ import (
 )
 
 var l2DB *L2DB
+var l2DBWithACC *L2DB
 var historyDB *historydb.HistoryDB
 var tc *til.Context
 var tokens map[common.TokenID]historydb.TokenWithUSD
@@ -34,9 +35,11 @@ func TestMain(m *testing.M) {
 	if err != nil {
 		panic(err)
 	}
-	l2DB = NewL2DB(db, 10, 1000, 24*time.Hour)
+	l2DB = NewL2DB(db, 10, 1000, 24*time.Hour, nil)
+	apiConnCon := dbUtils.NewAPICnnectionController(1, time.Second)
+	l2DBWithACC = NewL2DB(db, 10, 1000, 24*time.Hour, apiConnCon)
 	test.WipeDB(l2DB.DB())
-	historyDB = historydb.NewHistoryDB(db)
+	historyDB = historydb.NewHistoryDB(db, nil)
 	// Run tests
 	result := m.Run()
 	// Close DB
@@ -267,7 +270,7 @@ func TestStartForging(t *testing.T) {
 	assert.NoError(t, err)
 	// Fetch txs and check that they've been updated correctly
 	for _, id := range startForgingTxIDs {
-		fetchedTx, err := l2DB.GetTxAPI(id)
+		fetchedTx, err := l2DBWithACC.GetTxAPI(id)
 		assert.NoError(t, err)
 		assert.Equal(t, common.PoolL2TxStateForging, fetchedTx.State)
 		assert.Equal(t, &fakeBatchNum, fetchedTx.BatchNum)
@@ -312,7 +315,7 @@ func TestDoneForging(t *testing.T) {
 
 	// Fetch txs and check that they've been updated correctly
 	for _, id := range doneForgingTxIDs {
-		fetchedTx, err := l2DB.GetTxAPI(id)
+		fetchedTx, err := l2DBWithACC.GetTxAPI(id)
 		assert.NoError(t, err)
 		assert.Equal(t, common.PoolL2TxStateForged, fetchedTx.State)
 		assert.Equal(t, &fakeBatchNum, fetchedTx.BatchNum)
@@ -344,7 +347,7 @@ func TestInvalidate(t *testing.T) {
 	assert.NoError(t, err)
 	// Fetch txs and check that they've been updated correctly
 	for _, id := range invalidTxIDs {
-		fetchedTx, err := l2DB.GetTxAPI(id)
+		fetchedTx, err := l2DBWithACC.GetTxAPI(id)
 		assert.NoError(t, err)
 		assert.Equal(t, common.PoolL2TxStateInvalid, fetchedTx.State)
 		assert.Equal(t, &fakeBatchNum, fetchedTx.BatchNum)
@@ -385,7 +388,7 @@ func TestInvalidateOldNonces(t *testing.T) {
 	assert.NoError(t, err)
 	// Fetch txs and check that they've been updated correctly
 	for _, id := range invalidTxIDs {
-		fetchedTx, err := l2DB.GetTxAPI(id)
+		fetchedTx, err := l2DBWithACC.GetTxAPI(id)
 		require.NoError(t, err)
 		assert.Equal(t, common.PoolL2TxStateInvalid, fetchedTx.State)
 		assert.Equal(t, &fakeBatchNum, fetchedTx.BatchNum)
@@ -460,13 +463,13 @@ func TestReorg(t *testing.T) {
 	err = l2DB.Reorg(lastValidBatch)
 	assert.NoError(t, err)
 	for _, id := range reorgedTxIDs {
-		tx, err := l2DB.GetTxAPI(id)
+		tx, err := l2DBWithACC.GetTxAPI(id)
 		assert.NoError(t, err)
 		assert.Nil(t, tx.BatchNum)
 		assert.Equal(t, common.PoolL2TxStatePending, tx.State)
 	}
 	for _, id := range nonReorgedTxIDs {
-		fetchedTx, err := l2DB.GetTxAPI(id)
+		fetchedTx, err := l2DBWithACC.GetTxAPI(id)
 		assert.NoError(t, err)
 		assert.Equal(t, lastValidBatch, *fetchedTx.BatchNum)
 	}
@@ -537,13 +540,13 @@ func TestReorg2(t *testing.T) {
 	err = l2DB.Reorg(lastValidBatch)
 	assert.NoError(t, err)
 	for _, id := range reorgedTxIDs {
-		tx, err := l2DB.GetTxAPI(id)
+		tx, err := l2DBWithACC.GetTxAPI(id)
 		assert.NoError(t, err)
 		assert.Nil(t, tx.BatchNum)
 		assert.Equal(t, common.PoolL2TxStatePending, tx.State)
 	}
 	for _, id := range nonReorgedTxIDs {
-		fetchedTx, err := l2DB.GetTxAPI(id)
+		fetchedTx, err := l2DBWithACC.GetTxAPI(id)
 		assert.NoError(t, err)
 		assert.Equal(t, lastValidBatch, *fetchedTx.BatchNum)
 	}

db/utils.go

@@ -1,16 +1,19 @@
 package db
 
 import (
+	"context"
 	"database/sql"
 	"fmt"
 	"math/big"
 	"reflect"
 	"strings"
+	"time"
 
 	"github.com/gobuffalo/packr/v2"
 	"github.com/hermeznetwork/hermez-node/log"
 	"github.com/hermeznetwork/tracerr"
 	"github.com/jmoiron/sqlx"
+	"github.com/marusama/semaphore/v2"
 	migrate "github.com/rubenv/sql-migrate"
 	"github.com/russross/meddler"
 )
@@ -84,6 +87,32 @@ func InitSQLDB(port int, host, user, password, name string) (*sqlx.DB, error) {
 	return db, nil
 }
 
+// APIConnectionController is used to limit the SQL open connections used by the API
+type APIConnectionController struct {
+	smphr   semaphore.Semaphore
+	timeout time.Duration
+}
+
+// NewAPICnnectionController initialize APIConnectionController
+func NewAPICnnectionController(maxConnections int, timeout time.Duration) *APIConnectionController {
+	return &APIConnectionController{
+		smphr:   semaphore.New(maxConnections),
+		timeout: timeout,
+	}
+}
+
+// Acquire reserves a SQL connection. If the connection is not acquired
+// within the timeout, the function will return an error
+func (acc *APIConnectionController) Acquire() (context.CancelFunc, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), acc.timeout) //nolint:govet
+	return cancel, acc.smphr.Acquire(ctx, 1)
+}
+
+// Release frees a SQL connection
+func (acc *APIConnectionController) Release() {
+	acc.smphr.Release(1)
+}
+
 // initMeddler registers tags to be used to read/write from SQL DBs using meddler
 func initMeddler() {
 	meddler.Register("bigint", BigIntMeddler{})

go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/jmoiron/sqlx v1.2.1-0.20200615141059-0794cb1f47ee
 	github.com/joho/godotenv v1.3.0
 	github.com/lib/pq v1.8.0
+	github.com/marusama/semaphore/v2 v2.4.1
 	github.com/mattn/go-sqlite3 v2.0.3+incompatible
 	github.com/miguelmota/go-ethereum-hdwallet v0.0.0-20200123000308-a60dcd172b4c
 	github.com/mitchellh/copystructure v1.0.0

go.sum

@@ -415,6 +415,9 @@ github.com/markbates/oncer v1.0.0 h1:E83IaVAHygyndzPimgUYJjbshhDTALZyXxvk9FOlQRY
 github.com/markbates/oncer v1.0.0/go.mod h1:Z59JA581E9GP6w96jai+TGqafHPW+cPfRxz2aSZ0mcI=
 github.com/markbates/safe v1.0.1 h1:yjZkbvRM6IzKj9tlu/zMJLS0n/V351OZWRnF3QfaUxI=
 github.com/markbates/safe v1.0.1/go.mod h1:nAqgmRi7cY2nqMc92/bSEeQA+R4OheNU2T1kNSCBdG0=
+github.com/marusama/semaphore v0.0.0-20190110074507-6952cef993b2 h1:sq+a5mb8zHbmHhrIH06oqIMGsanjpbxNgxEgZVfgpvQ=
+github.com/marusama/semaphore/v2 v2.4.1 h1:Y29DhhFMvreVgoqF9EtaSJAF9t2E7Sk7i5VW81sqB8I=
+github.com/marusama/semaphore/v2 v2.4.1/go.mod h1:z9nMiNUekt/LTpTUQdpp+4sJeYqUGpwMHfW0Z8V8fnQ=
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-colorable v0.1.0/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-colorable v0.1.2 h1:/bC9yWikZXAL9uJdulbSfyVNIR3n3trXl+v8+1sx8mU=

node/node.go

@@ -83,8 +83,15 @@ func NewNode(mode Mode, cfg *config.Node) (*Node, error) {
 	if err != nil {
 		return nil, tracerr.Wrap(err)
 	}
+	var apiConnCon *dbUtils.APIConnectionController
+	if cfg.API.Explorer || mode == ModeCoordinator {
+		apiConnCon = dbUtils.NewAPICnnectionController(
+			cfg.API.MaxSQLConnections,
+			cfg.API.SQLConnectionTimeout.Duration,
+		)
+	}
 
-	historyDB := historydb.NewHistoryDB(db)
+	historyDB := historydb.NewHistoryDB(db, apiConnCon)
 
 	ethClient, err := ethclient.Dial(cfg.Web3.URL)
 	if err != nil {
@@ -193,6 +200,7 @@ func NewNode(mode Mode, cfg *config.Node) (*Node, error) {
 			cfg.Coordinator.L2DB.SafetyPeriod,
 			cfg.Coordinator.L2DB.MaxTxs,
 			cfg.Coordinator.L2DB.TTL.Duration,
+			apiConnCon,
 		)
 
 		// Unlock FeeAccount EthAddr in the keystore to generate the

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)
+	historyDB := historydb.NewHistoryDB(db, nil)
 	// Clean DB
 	test.WipeDB(historyDB.DB())
 	// Populate DB
@@ -46,8 +46,7 @@ func TestPriceUpdater(t *testing.T) {
 	// Update prices
 	pu.UpdatePrices(context.Background())
 	// Check that prices have been updated
-	limit := uint(10)
+	fetchedTokens, err := historyDB.GetTokensTest()
-	fetchedTokens, _, err := historyDB.GetTokens(nil, nil, "", nil, &limit, historydb.OrderAsc)
 	require.NoError(t, err)
 	// TokenID 0 (ETH) is always on the DB
 	assert.Equal(t, 2, len(fetchedTokens))

synchronizer/synchronizer_test.go

@@ -314,7 +314,7 @@ 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)
+	historyDB := historydb.NewHistoryDB(db, nil)
 	// Clear DB
 	test.WipeDB(historyDB.DB())
 

test/zkproof/flows_test.go

@@ -38,7 +38,7 @@ func addTokens(t *testing.T, tc *til.Context, db *sqlx.DB) {
 		})
 	}
 
-	hdb := historydb.NewHistoryDB(db)
+	hdb := historydb.NewHistoryDB(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, 24*time.Hour)
+	l2DB := l2db.NewL2DB(db, 10, 100, 24*time.Hour, nil)
 
 	dir, err := ioutil.TempDir("", "tmpSyncDB")
 	require.NoError(t, err)

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, 24*time.Hour)
+	l2DB := l2db.NewL2DB(db, 10, 100, 24*time.Hour, nil)
 
 	dir, err := ioutil.TempDir("", "tmpdb")
 	require.NoError(t, err)
@@ -105,7 +105,7 @@ func addTokens(t *testing.T, tc *til.Context, db *sqlx.DB) {
 		})
 	}
 
-	hdb := historydb.NewHistoryDB(db)
+	hdb := historydb.NewHistoryDB(db, nil)
 	assert.NoError(t, hdb.AddBlock(&common.Block{
 		Num: 1,
 	}))