// FindAllShardsInKeyspace reads and returns all the existing shards in
// a keyspace. It doesn't take any lock.
func FindAllShardsInKeyspace(ts Server, keyspace string) (map[string]*ShardInfo, error) {
shards, err := ts.GetShardNames(keyspace)
if err != nil {
return nil, err
}
result := make(map[string]*ShardInfo, len(shards))
wg := sync.WaitGroup{}
mu := sync.Mutex{}
rec := concurrency.FirstErrorRecorder{}
for _, shard := range shards {
wg.Add(1)
go func(shard string) {
defer wg.Done()
si, err := ts.GetShard(keyspace, shard)
if err != nil {
rec.RecordError(fmt.Errorf("GetShard(%v,%v) failed: %v", keyspace, shard, err))
return
}
mu.Lock()
result[shard] = si
mu.Unlock()
}(shard)
}
wg.Wait()
if rec.HasErrors() {
return nil, rec.Error()
}
return result, nil
}
// Clone will do all the necessary actions to copy all the data from a
// source to a set of destinations.
func (wr *Wrangler) Clone(srcTabletAlias topo.TabletAlias, dstTabletAliases []topo.TabletAlias, forceMasterSnapshot bool, snapshotConcurrency, fetchConcurrency, fetchRetryCount int, serverMode bool) error {
// make sure the destination can be restored into (otherwise
// there is no point in taking the snapshot in the first place),
// and reserve it.
reserved := make([]topo.TabletAlias, 0, len(dstTabletAliases))
for _, dstTabletAlias := range dstTabletAliases {
err := wr.ReserveForRestore(srcTabletAlias, dstTabletAlias)
if err != nil {
wr.UnreserveForRestoreMulti(reserved)
return err
}
reserved = append(reserved, dstTabletAlias)
wr.Logger().Infof("Successfully reserved %v for restore", dstTabletAlias)
}
// take the snapshot, or put the server in SnapshotSource mode
// srcFilePath, parentAlias, slaveStartRequired, readWrite
sr, originalType, err := wr.Snapshot(srcTabletAlias, forceMasterSnapshot, snapshotConcurrency, serverMode)
if err != nil {
// The snapshot failed so un-reserve the destinations and return
wr.UnreserveForRestoreMulti(reserved)
return err
}
// try to restore the snapshot
// In serverMode, and in the case where we're replicating from
// the master, we can't wait for replication, as the master is down.
wg := sync.WaitGroup{}
rec := concurrency.FirstErrorRecorder{}
for _, dstTabletAlias := range dstTabletAliases {
wg.Add(1)
go func(dstTabletAlias topo.TabletAlias) {
e := wr.Restore(srcTabletAlias, sr.ManifestPath, dstTabletAlias, sr.ParentAlias, fetchConcurrency, fetchRetryCount, true, serverMode && originalType == topo.TYPE_MASTER)
rec.RecordError(e)
wg.Done()
}(dstTabletAlias)
}
wg.Wait()
err = rec.Error()
// in any case, fix the server
if serverMode {
resetErr := wr.SnapshotSourceEnd(srcTabletAlias, sr.SlaveStartRequired, sr.ReadOnly, originalType)
if resetErr != nil {
if err == nil {
// If there is no other error, this matters.
err = resetErr
} else {
// In the context of a larger failure, just log a note to cleanup.
wr.Logger().Errorf("Failed to reset snapshot source: %v - vtctl SnapshotSourceEnd is required", resetErr)
}
}
}
return err
}
// This function should only be used with an action lock on the keyspace
// - otherwise the consistency of the serving graph data can't be
// guaranteed.
//
// Take data from the global keyspace and rebuild the local serving
// copies in each cell.
func (wr *Wrangler) rebuildKeyspace(keyspace string, cells []string) error {
wr.logger.Infof("rebuildKeyspace %v", keyspace)
ki, err := wr.ts.GetKeyspace(keyspace)
if err != nil {
return err
}
shards, err := wr.ts.GetShardNames(keyspace)
if err != nil {
return err
}
// Rebuild all shards in parallel, save the shards
shardCache := make(map[string]*topo.ShardInfo)
wg := sync.WaitGroup{}
mu := sync.Mutex{}
rec := concurrency.FirstErrorRecorder{}
for _, shard := range shards {
wg.Add(1)
go func(shard string) {
if shardInfo, err := wr.RebuildShardGraph(keyspace, shard, cells); err != nil {
rec.RecordError(fmt.Errorf("RebuildShardGraph failed: %v/%v %v", keyspace, shard, err))
} else {
mu.Lock()
shardCache[shard] = shardInfo
mu.Unlock()
}
wg.Done()
}(shard)
}
wg.Wait()
if rec.HasErrors() {
return rec.Error()
}
// Build the list of cells to work on: we get the union
// of all the Cells of all the Shards, limited to the provided cells.
//
// srvKeyspaceMap is a map:
// key: cell
// value: topo.SrvKeyspace object being built
srvKeyspaceMap := make(map[string]*topo.SrvKeyspace)
wr.findCellsForRebuild(ki, shardCache, cells, srvKeyspaceMap)
// Then we add the cells from the keyspaces we might be 'ServedFrom'.
for _, ksf := range ki.ServedFromMap {
servedFromShards, err := topo.FindAllShardsInKeyspace(wr.ts, ksf.Keyspace)
if err != nil {
return err
}
wr.findCellsForRebuild(ki, servedFromShards, cells, srvKeyspaceMap)
}
// for each entry in the srvKeyspaceMap map, we do the following:
// - read the SrvShard structures for each shard / cell
// - if not present, build an empty one from global Shard
// - compute the union of the db types (replica, master, ...)
// - sort the shards in the list by range
// - check the ranges are compatible (no hole, covers everything)
for cell, srvKeyspace := range srvKeyspaceMap {
keyspaceDbTypes := make(map[topo.TabletType]bool)
srvKeyspace.Partitions = make(map[topo.TabletType]*topo.KeyspacePartition)
for shard, si := range shardCache {
srvShard, err := wr.ts.GetSrvShard(cell, keyspace, shard)
switch err {
case nil:
// we keep going
case topo.ErrNoNode:
wr.logger.Infof("Cell %v for %v/%v has no SvrShard, using Shard data with no TabletTypes instead", cell, keyspace, shard)
srvShard = &topo.SrvShard{
Name: si.ShardName(),
KeyRange: si.KeyRange,
ServedTypes: si.GetServedTypesPerCell(cell),
MasterCell: si.MasterAlias.Cell,
}
default:
return err
}
for _, tabletType := range srvShard.TabletTypes {
keyspaceDbTypes[tabletType] = true
}
// for each type this shard is supposed to serve,
// add it to srvKeyspace.Partitions
for _, tabletType := range srvShard.ServedTypes {
if _, ok := srvKeyspace.Partitions[tabletType]; !ok {
srvKeyspace.Partitions[tabletType] = &topo.KeyspacePartition{
Shards: make([]topo.SrvShard, 0)}
}
srvKeyspace.Partitions[tabletType].Shards = append(srvKeyspace.Partitions[tabletType].Shards, *srvShard)
}
}
srvKeyspace.TabletTypes = make([]topo.TabletType, 0, len(keyspaceDbTypes))
for dbType := range keyspaceDbTypes {
srvKeyspace.TabletTypes = append(srvKeyspace.TabletTypes, dbType)
}
if err := wr.checkPartitions(cell, srvKeyspace); err != nil {
return err
}
}
// and then finally save the keyspace objects
for cell, srvKeyspace := range srvKeyspaceMap {
wr.logger.Infof("updating keyspace serving graph in cell %v for %v", cell, keyspace)
if err := wr.ts.UpdateSrvKeyspace(cell, keyspace, srvKeyspace); err != nil {
return fmt.Errorf("writing serving data failed: %v", err)
}
}
return nil
}