// replicaMigrateServedFrom handles the slave (replica, rdonly) migration.
func (wr *Wrangler) replicaMigrateServedFrom(ctx context.Context, ki *topo.KeyspaceInfo, sourceShard *topo.ShardInfo, destinationShard *topo.ShardInfo, servedType topodatapb.TabletType, cells []string, reverse bool, tables []string, ev *events.MigrateServedFrom) error {
// Save the destination keyspace (its ServedFrom has been changed)
event.DispatchUpdate(ev, "updating keyspace")
if err := wr.ts.UpdateKeyspace(ctx, ki); err != nil {
return err
}
// Save the source shard (its blacklisted tables field has changed)
event.DispatchUpdate(ev, "updating source shard")
if err := sourceShard.UpdateSourceBlacklistedTables(servedType, cells, reverse, tables); err != nil {
return fmt.Errorf("UpdateSourceBlacklistedTables(%v/%v) failed: %v", sourceShard.Keyspace(), sourceShard.ShardName(), err)
}
if err := wr.ts.UpdateShard(ctx, sourceShard); err != nil {
return fmt.Errorf("UpdateShard(%v/%v) failed: %v", sourceShard.Keyspace(), sourceShard.ShardName(), err)
}
// Now refresh the source servers so they reload their
// blacklisted table list
event.DispatchUpdate(ev, "refreshing sources tablets state so they update their blacklisted tables")
if err := wr.RefreshTablesByShard(ctx, sourceShard, servedType, cells); err != nil {
return err
}
return nil
}
// masterMigrateServedFrom handles the master migration. The ordering is
// a bit different than for rdonly / replica to guarantee a smooth transition.
//
// The order is as follows:
// - Add BlacklistedTables on the source shard map for master
// - Refresh the source master, so it stops writing on the tables
// - Get the source master position, wait until destination master reaches it
// - Clear SourceShard on the destination Shard
// - Refresh the destination master, so its stops its filtered
// replication and starts accepting writes
func (wr *Wrangler) masterMigrateServedFrom(ctx context.Context, ki *topo.KeyspaceInfo, sourceShard *topo.ShardInfo, destinationShard *topo.ShardInfo, tables []string, ev *events.MigrateServedFrom, filteredReplicationWaitTime time.Duration) error {
// Read the data we need
sourceMasterTabletInfo, err := wr.ts.GetTablet(ctx, sourceShard.MasterAlias)
if err != nil {
return err
}
destinationMasterTabletInfo, err := wr.ts.GetTablet(ctx, destinationShard.MasterAlias)
if err != nil {
return err
}
// Update source shard (more blacklisted tables)
event.DispatchUpdate(ev, "updating source shard")
if err := sourceShard.UpdateSourceBlacklistedTables(topodatapb.TabletType_MASTER, nil, false, tables); err != nil {
return fmt.Errorf("UpdateSourceBlacklistedTables(%v/%v) failed: %v", sourceShard.Keyspace(), sourceShard.ShardName(), err)
}
if err := wr.ts.UpdateShard(ctx, sourceShard); err != nil {
return fmt.Errorf("UpdateShard(%v/%v) failed: %v", sourceShard.Keyspace(), sourceShard.ShardName(), err)
}
// Now refresh the blacklisted table list on the source master
event.DispatchUpdate(ev, "refreshing source master so it updates its blacklisted tables")
if err := wr.tmc.RefreshState(ctx, sourceMasterTabletInfo); err != nil {
return err
}
// get the position
event.DispatchUpdate(ev, "getting master position")
masterPosition, err := wr.tmc.MasterPosition(ctx, sourceMasterTabletInfo)
if err != nil {
return err
}
// wait for it
event.DispatchUpdate(ev, "waiting for destination master to catch up to source master")
if err := wr.tmc.WaitBlpPosition(ctx, destinationMasterTabletInfo, &tabletmanagerdatapb.BlpPosition{
Uid: 0,
Position: masterPosition,
}, filteredReplicationWaitTime); err != nil {
return err
}
// Update the destination keyspace (its ServedFrom has changed)
event.DispatchUpdate(ev, "updating keyspace")
if err = wr.ts.UpdateKeyspace(ctx, ki); err != nil {
return err
}
// Update the destination shard (no more source shard)
event.DispatchUpdate(ev, "updating destination shard")
destinationShard.SourceShards = nil
if err := wr.ts.UpdateShard(ctx, destinationShard); err != nil {
return err
}
// Tell the new shards masters they can now be read-write.
// Invoking a remote action will also make the tablet stop filtered
// replication.
event.DispatchUpdate(ev, "setting destination shard masters read-write")
if err := wr.refreshMasters(ctx, []*topo.ShardInfo{destinationShard}); err != nil {
return err
}
return nil
}