graph/db: batch fetch channel data in forEachNodeChannel

Update the forEachNodeChannel helper to batch fetch channel data.

graph/db/sql_store.go

@@ -757,7 +757,7 @@ func (s *SQLStore) ForEachSourceNodeChannel(ctx context.Context,
 		}
 
 		return forEachNodeChannel(
-			ctx, db, s.cfg.ChainHash, nodeID,
+			ctx, db, s.cfg, nodeID,
 			func(info *models.ChannelEdgeInfo,
 				outPolicy *models.ChannelEdgePolicy,
 				_ *models.ChannelEdgePolicy) error {
@@ -815,7 +815,7 @@ func (s *SQLStore) ForEachNode(ctx context.Context,
 				node *models.LightningNode) error {
 
 				return cb(newSQLGraphNodeTx(
-					db, s.cfg.ChainHash, dbNodeID, node,
+					db, s.cfg, dbNodeID, node,
 				))
 			},
 		)
@@ -828,19 +828,19 @@ type sqlGraphNodeTx struct {
 	db   SQLQueries
 	id   int64
 	node *models.LightningNode
-	chain chainhash.Hash
+	cfg  *SQLStoreConfig
 }
 
 // A compile-time constraint to ensure sqlGraphNodeTx implements the NodeRTx
 // interface.
 var _ NodeRTx = (*sqlGraphNodeTx)(nil)
 
-func newSQLGraphNodeTx(db SQLQueries, chain chainhash.Hash,
+func newSQLGraphNodeTx(db SQLQueries, cfg *SQLStoreConfig,
 	id int64, node *models.LightningNode) *sqlGraphNodeTx {
 
 	return &sqlGraphNodeTx{
 		db:   db,
-		chain: chain,
+		cfg:  cfg,
 		id:   id,
 		node: node,
 	}
@@ -862,7 +862,7 @@ func (s *sqlGraphNodeTx) ForEachChannel(cb func(*models.ChannelEdgeInfo,
 
 	ctx := context.TODO()
 
-	return forEachNodeChannel(ctx, s.db, s.chain, s.id, cb)
+	return forEachNodeChannel(ctx, s.db, s.cfg, s.id, cb)
 }
 
 // FetchNode fetches the node with the given pub key under the same transaction
@@ -879,7 +879,7 @@ func (s *sqlGraphNodeTx) FetchNode(nodePub route.Vertex) (NodeRTx, error) {
 			nodePub, err)
 	}
 
-	return newSQLGraphNodeTx(s.db, s.chain, id, node), nil
+	return newSQLGraphNodeTx(s.db, s.cfg, id, node), nil
 }
 
 // ForEachNodeDirectedChannel iterates through all channels of a given node,
@@ -952,9 +952,7 @@ func (s *SQLStore) ForEachNodeChannel(ctx context.Context, nodePub route.Vertex,
 			return fmt.Errorf("unable to fetch node: %w", err)
 		}
 
-		return forEachNodeChannel(
+		return forEachNodeChannel(ctx, db, s.cfg, dbNode.ID, cb)
-			ctx, db, s.cfg.ChainHash, dbNode.ID, cb,
-		)
 	}, reset)
 }
 
@@ -3073,11 +3071,11 @@ func forEachNodeCacheable(ctx context.Context, cfg *sqldb.QueryConfig,
 // edge information, the outgoing policy and the incoming policy for the
 // channel and node combo.
 func forEachNodeChannel(ctx context.Context, db SQLQueries,
-	chain chainhash.Hash, id int64, cb func(*models.ChannelEdgeInfo,
+	cfg *SQLStoreConfig, id int64, cb func(*models.ChannelEdgeInfo,
 		*models.ChannelEdgePolicy,
 		*models.ChannelEdgePolicy) error) error {
 
-	// Get all the V1 channels for this node.Add commentMore actions
+	// Get all the V1 channels for this node.
 	rows, err := db.ListChannelsByNodeID(
 		ctx, sqlc.ListChannelsByNodeIDParams{
 			Version: int16(ProtocolV1),
@@ -3088,6 +3086,29 @@ func forEachNodeChannel(ctx context.Context, db SQLQueries,
 		return fmt.Errorf("unable to fetch channels: %w", err)
 	}
 
+	// Collect all the channel and policy IDs.
+	var (
+		chanIDs   = make([]int64, 0, len(rows))
+		policyIDs = make([]int64, 0, 2*len(rows))
+	)
+	for _, row := range rows {
+		chanIDs = append(chanIDs, row.GraphChannel.ID)
+
+		if row.Policy1ID.Valid {
+			policyIDs = append(policyIDs, row.Policy1ID.Int64)
+		}
+		if row.Policy2ID.Valid {
+			policyIDs = append(policyIDs, row.Policy2ID.Int64)
+		}
+	}
+
+	batchData, err := batchLoadChannelData(
+		ctx, cfg.QueryCfg, db, chanIDs, policyIDs,
+	)
+	if err != nil {
+		return fmt.Errorf("unable to batch load channel data: %w", err)
+	}
+
 	// Call the call-back for each channel and its known policies.
 	for _, row := range rows {
 		node1, node2, err := buildNodeVertices(
@@ -3098,8 +3119,9 @@ func forEachNodeChannel(ctx context.Context, db SQLQueries,
 				err)
 		}
 
-		edge, err := getAndBuildEdgeInfo(
+		edge, err := buildEdgeInfoWithBatchData(
-			ctx, db, chain, row.GraphChannel, node1, node2,
+			cfg.ChainHash, row.GraphChannel, node1, node2,
+			batchData,
 		)
 		if err != nil {
 			return fmt.Errorf("unable to build channel info: %w",
@@ -3112,8 +3134,8 @@ func forEachNodeChannel(ctx context.Context, db SQLQueries,
 				"policies: %w", err)
 		}
 
-		p1, p2, err := getAndBuildChanPolicies(
+		p1, p2, err := buildChanPoliciesWithBatchData(
-			ctx, db, dbPol1, dbPol2, edge.ChannelID, node1, node2,
+			dbPol1, dbPol2, edge.ChannelID, node1, node2, batchData,
 		)
 		if err != nil {
 			return fmt.Errorf("unable to build channel "+