diff --git a/internal/bus/chainsubscriber.go b/internal/bus/chainsubscriber.go
index 9445e2f19..23da73cfa 100644
--- a/internal/bus/chainsubscriber.go
+++ b/internal/bus/chainsubscriber.go
@@ -200,7 +200,7 @@ func (s *chainSubscriber) applyChainUpdate(tx sql.ChainUpdateTx, cau chain.Apply
 	cau.ForEachFileContractElement(func(fce types.FileContractElement, created bool, rev *types.FileContractElement, resolved, valid bool) {
 		if err != nil {
 			return
-		} else if known, lookupErr := tx.IsKnownContract(fce.ID); err != nil {
+		} else if known, lookupErr := tx.IsKnownContract(fce.ID); lookupErr != nil {
 			err = lookupErr
 			return
 		} else if !known {
@@ -217,7 +217,7 @@ func (s *chainSubscriber) applyChainUpdate(tx sql.ChainUpdateTx, cau chain.Apply
 	cau.ForEachV2FileContractElement(func(fce types.V2FileContractElement, created bool, rev *types.V2FileContractElement, res types.V2FileContractResolutionType) {
 		if err != nil {
 			return
-		} else if known, lookupErr := tx.IsKnownContract(fce.ID); err != nil {
+		} else if known, lookupErr := tx.IsKnownContract(fce.ID); lookupErr != nil {
 			err = lookupErr
 			return
 		} else if !known {
@@ -268,7 +268,7 @@ func (s *chainSubscriber) revertChainUpdate(tx sql.ChainUpdateTx, cru chain.Reve
 	cru.ForEachFileContractElement(func(fce types.FileContractElement, created bool, rev *types.FileContractElement, resolved, _ bool) {
 		if err != nil {
 			return
-		} else if known, lookupErr := tx.IsKnownContract(fce.ID); err != nil {
+		} else if known, lookupErr := tx.IsKnownContract(fce.ID); lookupErr != nil {
 			err = lookupErr
 			return
 		} else if !known {
@@ -285,7 +285,7 @@ func (s *chainSubscriber) revertChainUpdate(tx sql.ChainUpdateTx, cru chain.Reve
 	cru.ForEachV2FileContractElement(func(fce types.V2FileContractElement, created bool, rev *types.V2FileContractElement, res types.V2FileContractResolutionType) {
 		if err != nil {
 			return
-		} else if known, lookupErr := tx.IsKnownContract(fce.ID); err != nil {
+		} else if known, lookupErr := tx.IsKnownContract(fce.ID); lookupErr != nil {
 			err = lookupErr
 			return
 		} else if !known {
diff --git a/stores/sql/chain.go b/stores/sql/chain.go
index 990c2c4cf..c872adfd0 100644
--- a/stores/sql/chain.go
+++ b/stores/sql/chain.go
@@ -205,10 +205,9 @@ func FileContractElement(ctx context.Context, tx sql.Tx, fcid types.FileContract
 }
 
 func IsKnownContract(ctx context.Context, tx sql.Tx, fcid types.FileContractID) (known bool, _ error) {
-	err := tx.QueryRow(ctx, "SELECT 1 FROM contracts WHERE fcid = ?", FileContractID(fcid)).Scan(&known)
-	if errors.Is(err, dsql.ErrNoRows) {
-		return false, nil
-	} else if err != nil {
+	err := tx.QueryRow(ctx, "SELECT EXISTS (SELECT 1 FROM contracts WHERE fcid = ?)", FileContractID(fcid)).
+		Scan(&known)
+	if err != nil {
 		return false, err
 	}
 	return known, nil
@@ -221,7 +220,7 @@ func RecordContractRenewal(ctx context.Context, tx sql.Tx, oldFCID, newFCID type
 	}
 	_, err = tx.Exec(ctx, "UPDATE contracts SET contracts.renewed_from = ? WHERE contracts.fcid = ?", FileContractID(oldFCID), FileContractID(newFCID))
 	if err != nil {
-		return fmt.Errorf("failed to update renewed_to of new contract: %w", err)
+		return fmt.Errorf("failed to update renewed_from of new contract: %w", err)
 	}
 	return nil
 }
diff --git a/stores/sql/mysql/chain.go b/stores/sql/mysql/chain.go
index 1d2683075..8d854fb27 100644
--- a/stores/sql/mysql/chain.go
+++ b/stores/sql/mysql/chain.go
@@ -212,10 +212,6 @@ func (c chainUpdateTx) FileContractElement(fcid types.FileContractID) (types.V2F
 }
 
 func (c chainUpdateTx) IsKnownContract(fcid types.FileContractID) (bool, error) {
-	if c.known == nil {
-		c.known = make(map[types.FileContractID]bool)
-	}
-
 	if relevant, ok := c.known[fcid]; ok {
 		return relevant, nil
 	}
diff --git a/stores/sql/mysql/main.go b/stores/sql/mysql/main.go
index 8d856fe8c..7dba272ec 100644
--- a/stores/sql/mysql/main.go
+++ b/stores/sql/mysql/main.go
@@ -654,9 +654,10 @@ func (tx *MainDatabaseTx) Peers(ctx context.Context) ([]syncer.PeerInfo, error)
 
 func (tx *MainDatabaseTx) ProcessChainUpdate(ctx context.Context, fn func(ssql.ChainUpdateTx) error) error {
 	return fn(&chainUpdateTx{
-		ctx: ctx,
-		tx:  tx,
-		l:   tx.log.Named("ProcessChainUpdate"),
+		ctx:   ctx,
+		known: make(map[types.FileContractID]bool),
+		tx:    tx,
+		l:     tx.log.Named("ProcessChainUpdate"),
 	})
 }
 
diff --git a/stores/sql/sqlite/chain.go b/stores/sql/sqlite/chain.go
index f3abf5353..cf642e8fe 100644
--- a/stores/sql/sqlite/chain.go
+++ b/stores/sql/sqlite/chain.go
@@ -213,10 +213,6 @@ func (c chainUpdateTx) FileContractElement(fcid types.FileContractID) (types.V2F
 }
 
 func (c chainUpdateTx) IsKnownContract(fcid types.FileContractID) (bool, error) {
-	if c.known == nil {
-		c.known = make(map[types.FileContractID]bool)
-	}
-
 	if relevant, ok := c.known[fcid]; ok {
 		return relevant, nil
 	}
diff --git a/stores/sql/sqlite/main.go b/stores/sql/sqlite/main.go
index 51fcd5592..0e488c6ed 100644
--- a/stores/sql/sqlite/main.go
+++ b/stores/sql/sqlite/main.go
@@ -650,9 +650,10 @@ func (tx *MainDatabaseTx) Peers(ctx context.Context) ([]syncer.PeerInfo, error)
 
 func (tx *MainDatabaseTx) ProcessChainUpdate(ctx context.Context, fn func(ssql.ChainUpdateTx) error) (err error) {
 	return fn(&chainUpdateTx{
-		ctx: ctx,
-		tx:  tx,
-		l:   tx.log.Named("ProcessChainUpdate"),
+		ctx:   ctx,
+		known: make(map[types.FileContractID]bool),
+		tx:    tx,
+		l:     tx.log.Named("ProcessChainUpdate"),
 	})
 }