graph/db+sqldb: make node migration idempotent

diff --git a/graph/db/sql_migration.go b/graph/db/sql_migration.go
index 45656e6..ae45aa9 100644
--- a/graph/db/sql_migration.go
+++ b/graph/db/sql_migration.go
@@ -273,7 +273,7 @@ func migrateNodes(ctx context.Context, cfg *sqldb.QueryConfig,
 		// production.
 
 		// Write the node to the SQL database.
-		id, err := upsertNode(ctx, sqlDB, node)
+		id, err := insertNodeSQLMig(ctx, sqlDB, node)
 		if err != nil {
 			return fmt.Errorf("could not persist node(%x): %w", pub,
 				err)
@@ -303,8 +303,11 @@ func migrateNodes(ctx context.Context, cfg *sqldb.QueryConfig,
 
 		return nil
 	}, func() {
-		// No reset is needed since if a retry occurs, the entire
-		// migration will be retried from the start.
+		count = 0
+		chunk = 0
+		skipped = 0
+		t0 = time.Now()
+		batch = make(map[int64]*models.LightningNode, cfg.MaxBatchSize)
 	})
 	if err != nil {
 		return fmt.Errorf("could not migrate nodes: %w", err)
@@ -1353,3 +1356,70 @@ func forEachClosedSCID(db kvdb.Backend,
 		})
 	}, reset)
 }
+
+// insertNodeSQLMig inserts the node record into the database during the graph
+// SQL migration. No error is expected if the node already exists. Unlike the
+// main upsertNode function, this function does not require that a new node
+// update have a newer timestamp than the existing one. This is because we want
+// the migration to be idempotent and dont want to error out if we re-insert the
+// exact same node.
+//
+// TODO(elle): update the upsert calls in this function to be more efficient.
+// since no data collection steps should be required during the migration.
+func insertNodeSQLMig(ctx context.Context, db SQLQueries,
+	node *models.LightningNode) (int64, error) {
+
+	params := sqlc.InsertNodeMigParams{
+		Version: int16(ProtocolV1),
+		PubKey:  node.PubKeyBytes[:],
+	}
+
+	if node.HaveNodeAnnouncement {
+		params.LastUpdate = sqldb.SQLInt64(node.LastUpdate.Unix())
+		params.Color = sqldb.SQLStr(EncodeHexColor(node.Color))
+		params.Alias = sqldb.SQLStr(node.Alias)
+		params.Signature = node.AuthSigBytes
+	}
+
+	nodeID, err := db.InsertNodeMig(ctx, params)
+	if err != nil {
+		return 0, fmt.Errorf("upserting node(%x): %w", node.PubKeyBytes,
+			err)
+	}
+
+	// We can exit here if we don't have the announcement yet.
+	if !node.HaveNodeAnnouncement {
+		return nodeID, nil
+	}
+
+	// NOTE: The upserts here will be updated to be more efficient in the
+	// following commits.
+
+	// Update the node's features.
+	err = upsertNodeFeatures(ctx, db, nodeID, node.Features)
+	if err != nil {
+		return 0, fmt.Errorf("inserting node features: %w", err)
+	}
+
+	// Update the node's addresses.
+	err = upsertNodeAddresses(ctx, db, nodeID, node.Addresses)
+	if err != nil {
+		return 0, fmt.Errorf("inserting node addresses: %w", err)
+	}
+
+	// Convert the flat extra opaque data into a map of TLV types to
+	// values.
+	extra, err := marshalExtraOpaqueData(node.ExtraOpaqueData)
+	if err != nil {
+		return 0, fmt.Errorf("unable to marshal extra opaque data: %w",
+			err)
+	}
+
+	// Update the node's extra signed fields.
+	err = upsertNodeExtraSignedFields(ctx, db, nodeID, extra)
+	if err != nil {
+		return 0, fmt.Errorf("inserting node extra TLVs: %w", err)
+	}
+
+	return nodeID, nil
+}
diff --git a/graph/db/sql_migration_test.go b/graph/db/sql_migration_test.go
index d4bba60..7826fd1 100644
--- a/graph/db/sql_migration_test.go
+++ b/graph/db/sql_migration_test.go
@@ -155,7 +155,6 @@ func TestMigrateGraphToSQL(t *testing.T) {
 			expGraphStats: graphStats{
 				numNodes: 6,
 			},
-			expNotRetrySafety: true,
 		},
 		{
 			name: "source node",
@@ -173,7 +172,6 @@ func TestMigrateGraphToSQL(t *testing.T) {
 				numNodes:   1,
 				srcNodeSet: true,
 			},
-			expNotRetrySafety: true,
 		},
 		{
 			name:  "channel with no policies",
diff --git a/graph/db/sql_store.go b/graph/db/sql_store.go
index 956b840..449c4f3 100644
--- a/graph/db/sql_store.go
+++ b/graph/db/sql_store.go
@@ -153,6 +153,16 @@ type SQLQueries interface {
 	InsertClosedChannel(ctx context.Context, scid []byte) error
 	IsClosedChannel(ctx context.Context, scid []byte) (bool, error)
 	GetClosedChannelsSCIDs(ctx context.Context, scids [][]byte) ([][]byte, error)
+
+	/*
+		Migration specific queries.
+
+		NOTE: these should not be used in code other than migrations.
+		Once sqldbv2 is in place, these can be removed from this struct
+		as then migrations will have their own dedicated queries
+		structs.
+	*/
+	InsertNodeMig(ctx context.Context, arg sqlc.InsertNodeMigParams) (int64, error)
 }
 
 // BatchedSQLQueries is a version of SQLQueries that's capable of batched
diff --git a/sqldb/sqlc/graph.sql.go b/sqldb/sqlc/graph.sql.go
index d27143c..7afe8b1 100644
--- a/sqldb/sqlc/graph.sql.go
+++ b/sqldb/sqlc/graph.sql.go
@@ -2445,6 +2445,61 @@ func (q *Queries) InsertNodeFeature(ctx context.Context, arg InsertNodeFeaturePa
 	return err
 }
 
+const insertNodeMig = `-- name: InsertNodeMig :one
+/* ─────────────────────────────────────────────
+   Migration specific queries
+
+   NOTE: once sqldbv2 is in place, these queries can be contained to a package
+   dedicated to the migration that requires it, and so we can then remove
+   it from the main set of "live" queries that the code-base has access to.
+   ────────────────────────────────────────────-
+*/
+
+INSERT INTO graph_nodes (
+    version, pub_key, alias, last_update, color, signature
+) VALUES (
+    $1, $2, $3, $4, $5, $6
+)
+ON CONFLICT (pub_key, version)
+    -- If a conflict occurs, we have already migrated this node. However, we
+    -- still need to do an "UPDATE SET" here instead of "DO NOTHING" because
+    -- otherwise, the "RETURNING id" part does not work.
+    DO UPDATE SET
+        alias = EXCLUDED.alias,
+        last_update = EXCLUDED.last_update,
+        color = EXCLUDED.color,
+        signature = EXCLUDED.signature
+RETURNING id
+`
+
+type InsertNodeMigParams struct {
+	Version    int16
+	PubKey     []byte
+	Alias      sql.NullString
+	LastUpdate sql.NullInt64
+	Color      sql.NullString
+	Signature  []byte
+}
+
+// NOTE: This query is only meant to be used by the graph SQL migration since
+// for that migration, in order to be retry-safe, we don't want to error out if
+// we re-insert the same node (which would error if the normal UpsertNode query
+// is used because of the constraint in that query that requires a node update
+// to have a newer last_update than the existing node).
+func (q *Queries) InsertNodeMig(ctx context.Context, arg InsertNodeMigParams) (int64, error) {
+	row := q.db.QueryRowContext(ctx, insertNodeMig,
+		arg.Version,
+		arg.PubKey,
+		arg.Alias,
+		arg.LastUpdate,
+		arg.Color,
+		arg.Signature,
+	)
+	var id int64
+	err := row.Scan(&id)
+	return id, err
+}
+
 const isClosedChannel = `-- name: IsClosedChannel :one
 SELECT EXISTS (
     SELECT 1
diff --git a/sqldb/sqlc/querier.go b/sqldb/sqlc/querier.go
index eaef3c7..7696e36 100644
--- a/sqldb/sqlc/querier.go
+++ b/sqldb/sqlc/querier.go
@@ -99,6 +99,12 @@ type Querier interface {
 	InsertMigratedInvoice(ctx context.Context, arg InsertMigratedInvoiceParams) (int64, error)
 	InsertNodeAddress(ctx context.Context, arg InsertNodeAddressParams) error
 	InsertNodeFeature(ctx context.Context, arg InsertNodeFeatureParams) error
+	// NOTE: This query is only meant to be used by the graph SQL migration since
+	// for that migration, in order to be retry-safe, we don't want to error out if
+	// we re-insert the same node (which would error if the normal UpsertNode query
+	// is used because of the constraint in that query that requires a node update
+	// to have a newer last_update than the existing node).
+	InsertNodeMig(ctx context.Context, arg InsertNodeMigParams) (int64, error)
 	IsClosedChannel(ctx context.Context, scid []byte) (bool, error)
 	IsPublicV1Node(ctx context.Context, pubKey []byte) (bool, error)
 	IsZombieChannel(ctx context.Context, arg IsZombieChannelParams) (bool, error)
diff --git a/sqldb/sqlc/queries/graph.sql b/sqldb/sqlc/queries/graph.sql
index 04f8140..82e9b87 100644
--- a/sqldb/sqlc/queries/graph.sql
+++ b/sqldb/sqlc/queries/graph.sql
@@ -995,3 +995,34 @@ SELECT EXISTS (
 SELECT scid
 FROM graph_closed_scids
 WHERE scid IN (sqlc.slice('scids')/*SLICE:scids*/);
+
+/* ─────────────────────────────────────────────
+   Migration specific queries
+
+   NOTE: once sqldbv2 is in place, these queries can be contained to a package
+   dedicated to the migration that requires it, and so we can then remove
+   it from the main set of "live" queries that the code-base has access to.
+   ────────────────────────────────────────────-
+*/
+
+-- NOTE: This query is only meant to be used by the graph SQL migration since
+-- for that migration, in order to be retry-safe, we don't want to error out if
+-- we re-insert the same node (which would error if the normal UpsertNode query
+-- is used because of the constraint in that query that requires a node update
+-- to have a newer last_update than the existing node).
+-- name: InsertNodeMig :one
+INSERT INTO graph_nodes (
+    version, pub_key, alias, last_update, color, signature
+) VALUES (
+    $1, $2, $3, $4, $5, $6
+)
+ON CONFLICT (pub_key, version)
+    -- If a conflict occurs, we have already migrated this node. However, we
+    -- still need to do an "UPDATE SET" here instead of "DO NOTHING" because
+    -- otherwise, the "RETURNING id" part does not work.
+    DO UPDATE SET
+        alias = EXCLUDED.alias,
+        last_update = EXCLUDED.last_update,
+        color = EXCLUDED.color,
+        signature = EXCLUDED.signature
+RETURNING id;