Golang Server.FindAllShardsInKeyspace方法代碼示例

// FindOverlappingShards will return an array of OverlappingShards
// for the provided keyspace.
// We do not support more than two overlapping shards (for instance,
// having 40-80, 40-60 and 40-50 in the same keyspace is not supported and
// will return an error).
// If shards don't perfectly overlap, they are not returned.
func FindOverlappingShards(ctx context.Context, ts topo.Server, keyspace string) ([]*OverlappingShards, error) {
	shardMap, err := ts.FindAllShardsInKeyspace(ctx, keyspace)
	if err != nil {
		return nil, err
	}

	return findOverlappingShards(shardMap)
}

// rebuildKeyspace 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 rebuildKeyspace(ctx context.Context, log logutil.Logger, ts topo.Server, keyspace string, cells []string, rebuildSrvShards bool) error {
	log.Infof("rebuildKeyspace %v", keyspace)

	ki, err := ts.GetKeyspace(ctx, keyspace)
	if err != nil {
		return err
	}

	var shardCache map[string]*topo.ShardInfo
	if rebuildSrvShards {
		shards, err := ts.GetShardNames(ctx, keyspace)
		if err != nil {
			return nil
		}

		// 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 := RebuildShard(ctx, log, ts, keyspace, shard, cells); err != nil {
					rec.RecordError(fmt.Errorf("RebuildShard 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()
		}

	} else {
		shardCache, err = ts.FindAllShardsInKeyspace(ctx, keyspace)
		if err != nil {
			return err
		}
	}

	// 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]*topodatapb.SrvKeyspace)
	findCellsForRebuild(ki, shardCache, cells, srvKeyspaceMap)

	// Then we add the cells from the keyspaces we might be 'ServedFrom'.
	for _, ksf := range ki.ServedFroms {
		servedFromShards, err := ts.FindAllShardsInKeyspace(ctx, ksf.Keyspace)
		if err != nil {
			return err
		}
		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 {
		for _, si := range shardCache {
			servedTypes := si.GetServedTypesPerCell(cell)

			// for each type this shard is supposed to serve,
			// add it to srvKeyspace.Partitions
			for _, tabletType := range servedTypes {
				partition := topoproto.SrvKeyspaceGetPartition(srvKeyspace, tabletType)
				if partition == nil {
					partition = &topodatapb.SrvKeyspace_KeyspacePartition{
						ServedType: tabletType,
					}
					srvKeyspace.Partitions = append(srvKeyspace.Partitions, partition)
				}
				partition.ShardReferences = append(partition.ShardReferences, &topodatapb.ShardReference{
					Name:     si.ShardName(),
					KeyRange: si.KeyRange,
				})
			}
		}

		if err := orderAndCheckPartitions(cell, srvKeyspace); err != nil {
			return err
		}
	}
//.........這裏部分代碼省略.........