WIP

Signed-off-by: Tim Vaillancourt <[email protected]>

go/vt/vtorc/db/generate_base.go

@@ -29,9 +29,10 @@ var TableNames = []string{
 	"global_recovery_disable",
 	"topology_recovery_steps",
 	"database_instance_stale_binlog_coordinates",
-	"vitess_tablet",
+	"vitess_cell",
 	"vitess_keyspace",
 	"vitess_shard",
+	"vitess_tablet",
 }
 
 // vtorcBackend is a list of SQL statements required to build the vtorc backend
@@ -307,6 +308,14 @@ CREATE TABLE vitess_shard (
 	PRIMARY KEY (keyspace, shard)
 )`,
 	`
+DROP TABLET IF EXISTS vitess_cell
+`,
+	`
+CREATE TABLE vitess_cell (
+	cell varchar(128) NOT NULL,
+	PRIMARY KEY (cell)
+)`,
+	`
 CREATE INDEX source_host_port_idx_database_instance_database_instance on database_instance (source_host, source_port)
 	`,
 	`

go/vt/vtorc/inst/cell_dao.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2025 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package inst
+
+import (
+	"vitess.io/vitess/go/vt/external/golib/sqlutils"
+	"vitess.io/vitess/go/vt/vtorc/db"
+)
+
+// ReadCells reads all the vitess cell names.
+func ReadCells() ([]string, error) {
+	cells := make([]string, 0)
+	query := `SELECT cell FROM vitess_cell`
+	err := db.QueryVTOrc(query, nil, func(row sqlutils.RowMap) error {
+		cells = append(cells, row.GetString("cell"))
+		return nil
+	})
+	return cells, err
+}
+
+// SaveCell saves the keyspace record against the keyspace name.
+func SaveCell(cell string) error {
+	_, err := db.ExecVTOrc(`REPLACE INTO vitess_cell (cell) VALUES(?)`, cell)
+	return err
+}
+
+// DeleteCell deletes a cell.
+func DeleteCell(cell string) (err error) {
+	_, err = db.ExecVTOrc(`DELETE FROM vitess_cell WHERE cell = ?`, cell)
+	return err
+}

go/vt/vtorc/logic/cell_discovery.go

@@ -0,0 +1,75 @@
+/*
+Copyright 2025 The Vitess Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package logic
+
+import (
+	"context"
+	"sync"
+
+	"vitess.io/vitess/go/vt/log"
+	"vitess.io/vitess/go/vt/topo"
+	"vitess.io/vitess/go/vt/vtorc/inst"
+)
+
+var refreshCellsMu sync.Mutex
+
+// RefreshCells refreshes the list of cells.
+func RefreshCells(ctx context.Context) error {
+	cellsCtx, cellsCancel := context.WithTimeout(ctx, topo.RemoteOperationTimeout)
+	defer cellsCancel()
+	cells, err := ts.GetKnownCells(cellsCtx)
+	if err != nil {
+		return err
+	}
+	return refreshCells(cells)
+}
+
+// refreshCells saves a slice of cells and removes
+// stale cells that were not updated.
+func refreshCells(cells []string) (err error) {
+	refreshCellsMu.Lock()
+	defer refreshCellsMu.Unlock()
+
+	// save cells.
+	updated := make(map[string]bool)
+	for _, cell := range cells {
+		err = inst.SaveCell(cell)
+		if err != nil {
+			log.Error(err)
+			return err
+		}
+		updated[cell] = true
+	}
+
+	// read all saved cells. the values should not
+	// be changing because we are holding a lock.
+	cells, err = inst.ReadCells()
+	if err != nil {
+		return err
+	}
+
+	// delete cells that are stale.
+	for _, cell := range cells {
+		if updated[cell] {
+			continue
+		}
+		if err = inst.DeleteCell(cell); err != nil {
+			return err
+		}
+	}
+	return nil
+}

go/vt/vtorc/logic/tablet_discovery.go

@@ -181,13 +181,14 @@ func refreshAllTablets(ctx context.Context) error {
 
 // refreshTabletsUsing refreshes tablets using a provided loader.
 func refreshTabletsUsing(ctx context.Context, loader func(tabletAlias string), forceRefresh bool) error {
-	// Get all cells.
-	ctx, cancel := context.WithTimeout(ctx, topo.RemoteOperationTimeout)
-	defer cancel()
-	cells, err := ts.GetKnownCells(ctx)
+	cells, err := inst.ReadCells()
 	if err != nil {
 		return err
 	}
+	if len(cells) == 0 {
+		log.Error("Found no cells")
+		return nil
+	}
 
 	// Get all tablets from all cells.
 	getTabletsCtx, getTabletsCancel := context.WithTimeout(ctx, topo.RemoteOperationTimeout)

go/vt/vtorc/logic/vtorc.go

@@ -321,6 +321,11 @@ func refreshAllInformation(ctx context.Context) error {
 	// Create an errgroup
 	eg, ctx := errgroup.WithContext(ctx)
 
+	// Refresh all cells.
+	eg.Go(func() error {
+		return RefreshCells(ctx)
+	})
+
 	// Refresh all keyspace information.
 	eg.Go(func() error {
 		return RefreshAllKeyspacesAndShards(ctx)