backend

Documentation

Index

• func MakeUUID(tableName string, engineID int32) (string, uuid.UUID)
• type Backend
• type CheckCtx
• type ChunkFlushStatus
• type ClosedEngine
  • func NewClosedEngine(backend Backend, logger log.Logger, uuid uuid.UUID, id int32) *ClosedEngine
  • func (engine *ClosedEngine) Cleanup(ctx context.Context) error
  • func (en ClosedEngine) GetID() int32
  • func (en ClosedEngine) GetUUID() uuid.UUID
  • func (engine *ClosedEngine) Import(ctx context.Context, regionSplitSize, regionSplitKeys int64) error
  • func (engine *ClosedEngine) Logger() log.Logger
• type EngineConfig
• type EngineFileSize
• type EngineManager
  • func MakeEngineManager(ab Backend) EngineManager
  • func (be EngineManager) OpenEngine(ctx context.Context, config *EngineConfig, tableName string, engineID int32) (*OpenedEngine, error)
  • func (be EngineManager) UnsafeCloseEngine(ctx context.Context, cfg *EngineConfig, tableName string, engineID int32) (*ClosedEngine, error)
  • func (be EngineManager) UnsafeCloseEngineWithUUID(ctx context.Context, cfg *EngineConfig, tag string, engineUUID uuid.UUID, ...) (*ClosedEngine, error)
• type EngineWriter
• type LocalEngineConfig
• type LocalWriterConfig
• type OpenedEngine
  • func (engine *OpenedEngine) Close(ctx context.Context) (*ClosedEngine, error)
  • func (engine *OpenedEngine) Flush(ctx context.Context) error
  • func (engine *OpenedEngine) GetEngineUUID() uuid.UUID
  • func (en OpenedEngine) GetID() int32
  • func (en OpenedEngine) GetUUID() uuid.UUID
  • func (engine *OpenedEngine) LocalWriter(ctx context.Context, cfg *LocalWriterConfig) (EngineWriter, error)
• type TargetInfoGetter

Functions

func MakeUUID

func MakeUUID(tableName string, engineID int32) (string, uuid.UUID)

MakeUUID generates a UUID for the engine and a tag for the engine.

Types

type Backend

type Backend interface {
	// Close the connection to the backend.
	Close()

	// RetryImportDelay returns the duration to sleep when retrying an import
	RetryImportDelay() time.Duration

	// ShouldPostProcess returns whether KV-specific post-processing should be
	// performed for this backend. Post-processing includes checksum and analyze.
	ShouldPostProcess() bool

	OpenEngine(ctx context.Context, config *EngineConfig, engineUUID uuid.UUID) error

	CloseEngine(ctx context.Context, config *EngineConfig, engineUUID uuid.UUID) error

	// ImportEngine imports engine data to the backend. If it returns ErrDuplicateDetected,
	// it means there is duplicate detected. For this situation, all data in the engine must be imported.
	// It's safe to reset or cleanup this engine.
	ImportEngine(ctx context.Context, engineUUID uuid.UUID, regionSplitSize, regionSplitKeys int64) error

	CleanupEngine(ctx context.Context, engineUUID uuid.UUID) error

	// FlushEngine ensures all KV pairs written to an open engine has been
	// synchronized, such that kill-9'ing Lightning afterwards and resuming from
	// checkpoint can recover the exact same content.
	//
	// This method is only relevant for local backend, and is no-op for all
	// other backends.
	FlushEngine(ctx context.Context, engineUUID uuid.UUID) error

	// FlushAllEngines performs FlushEngine on all opened engines. This is a
	// very expensive operation and should only be used in some rare situation
	// (e.g. preparing to resolve a disk quota violation).
	FlushAllEngines(ctx context.Context) error

	// ResetEngine clears all written KV pairs in this opened engine.
	ResetEngine(ctx context.Context, engineUUID uuid.UUID) error

	// LocalWriter obtains a thread-local EngineWriter for writing rows into the given engine.
	LocalWriter(ctx context.Context, cfg *LocalWriterConfig, engineUUID uuid.UUID) (EngineWriter, error)
}

Backend defines the interface for a backend. Implementations of this interface must be goroutine safe: you can share an instance and execute any method anywhere. Usual workflow:

1. Create a `Backend` for the whole process.
2. For each table, i. Split into multiple "batches" consisting of data files with roughly equal total size. ii. For each batch, a. Create an `OpenedEngine` via `backend.OpenEngine()` b. For each chunk, deliver data into the engine via `engine.WriteRows()` c. When all chunks are written, obtain a `ClosedEngine` via `engine.Close()` d. Import data via `engine.Import()` e. Cleanup via `engine.Cleanup()`
3. Close the connection via `backend.Close()`

type CheckCtx

type CheckCtx struct {
	DBMetas []*mydump.MDDatabaseMeta
}

CheckCtx contains all parameters used in CheckRequirements

type ChunkFlushStatus

type ChunkFlushStatus interface {
	Flushed() bool
}

ChunkFlushStatus is the status of a chunk flush.

type ClosedEngine

type ClosedEngine struct {
	// contains filtered or unexported fields
}

ClosedEngine represents a closed engine, allowing ingestion into the target. This type is goroutine safe: you can share an instance and execute any method anywhere.

func NewClosedEngine

func NewClosedEngine(backend Backend, logger log.Logger, uuid uuid.UUID, id int32) *ClosedEngine

NewClosedEngine creates a new ClosedEngine.

func (*ClosedEngine) Cleanup

func (engine *ClosedEngine) Cleanup(ctx context.Context) error

Cleanup deletes the intermediate data from target.

func (ClosedEngine) GetID

func (en ClosedEngine) GetID() int32

GetID get engine id.

func (ClosedEngine) GetUUID

func (en ClosedEngine) GetUUID() uuid.UUID

func (*ClosedEngine) Import

func (engine *ClosedEngine) Import(ctx context.Context, regionSplitSize, regionSplitKeys int64) error

Import the data written to the engine into the target.

func (*ClosedEngine) Logger

func (engine *ClosedEngine) Logger() log.Logger

Logger returns the logger for the engine.

type EngineConfig

type EngineConfig struct {
	// TableInfo is the corresponding tidb table info
	TableInfo *checkpoints.TidbTableInfo
	// local backend specified configuration
	Local LocalEngineConfig
	// KeepSortDir indicates whether to keep the temporary sort directory
	// when opening the engine, instead of removing it.
	KeepSortDir bool
}

EngineConfig defines configuration used for open engine

type EngineFileSize

type EngineFileSize struct {
	// UUID is the engine's UUID.
	UUID uuid.UUID
	// DiskSize is the estimated total file size on disk right now.
	DiskSize int64
	// MemSize is the total memory size used by the engine. This is the
	// estimated additional size saved onto disk after calling Flush().
	MemSize int64
	// IsImporting indicates whether the engine performing Import().
	IsImporting bool
}

EngineFileSize represents the size of an engine on disk and in memory.

type EngineManager

type EngineManager struct {
	// contains filtered or unexported fields
}

EngineManager is the manager of engines. this is a wrapper of Backend, which provides some common methods for managing engines. and it has no states, can be created on demand

func MakeEngineManager

func MakeEngineManager(ab Backend) EngineManager

MakeEngineManager creates a new Backend from an Backend.

func (EngineManager) OpenEngine

func (be EngineManager) OpenEngine(ctx context.Context, config *EngineConfig,
	tableName string, engineID int32) (*OpenedEngine, error)

OpenEngine opens an engine with the given table name and engine ID.

func (EngineManager) UnsafeCloseEngine

func (be EngineManager) UnsafeCloseEngine(ctx context.Context, cfg *EngineConfig,
	tableName string, engineID int32) (*ClosedEngine, error)

UnsafeCloseEngine closes the engine without first opening it. This method is "unsafe" as it does not follow the normal operation sequence (Open -> Write -> Close -> Import). This method should only be used when one knows via other ways that the engine has already been opened, e.g. when resuming from a checkpoint.

func (EngineManager) UnsafeCloseEngineWithUUID

func (be EngineManager) UnsafeCloseEngineWithUUID(ctx context.Context, cfg *EngineConfig, tag string,
	engineUUID uuid.UUID, id int32) (*ClosedEngine, error)

UnsafeCloseEngineWithUUID closes the engine without first opening it. This method is "unsafe" as it does not follow the normal operation sequence (Open -> Write -> Close -> Import). This method should only be used when one knows via other ways that the engine has already been opened, e.g. when resuming from a checkpoint.

type EngineWriter

type EngineWriter interface {
	AppendRows(ctx context.Context, columnNames []string, rows encode.Rows) error
	IsSynced() bool
	Close(ctx context.Context) (ChunkFlushStatus, error)
}

EngineWriter is the interface for writing data to an engine.

type LocalEngineConfig

type LocalEngineConfig struct {
	// compact small SSTs before ingest into pebble
	Compact bool
	// raw kvs size threshold to trigger compact
	CompactThreshold int64
	// compact routine concurrency
	CompactConcurrency int
}

LocalEngineConfig is the configuration used for local backend in OpenEngine.

type LocalWriterConfig

type LocalWriterConfig struct {
	// is the chunk KV written to this LocalWriter sent in order
	// only needed for local backend, can omit for tidb backend
	IsKVSorted bool
	// only needed for tidb backend, can omit for local backend
	TableName string
}

LocalWriterConfig defines the configuration to open a LocalWriter

type OpenedEngine

type OpenedEngine struct {
	// contains filtered or unexported fields
}

OpenedEngine is an opened engine, allowing data to be written via WriteRows. This type is goroutine safe: you can share an instance and execute any method anywhere.

func (*OpenedEngine) Close

func (engine *OpenedEngine) Close(ctx context.Context) (*ClosedEngine, error)

Close the opened engine to prepare it for importing.

func (*OpenedEngine) Flush

func (engine *OpenedEngine) Flush(ctx context.Context) error

Flush current written data for local backend

func (*OpenedEngine) GetEngineUUID

func (engine *OpenedEngine) GetEngineUUID() uuid.UUID

GetEngineUUID returns the engine UUID.

func (OpenedEngine) GetID

func (en OpenedEngine) GetID() int32

GetID get engine id.

func (OpenedEngine) GetUUID

func (en OpenedEngine) GetUUID() uuid.UUID

func (*OpenedEngine) LocalWriter

func (engine *OpenedEngine) LocalWriter(ctx context.Context, cfg *LocalWriterConfig) (EngineWriter, error)

LocalWriter returns a writer that writes to the local backend.

type TargetInfoGetter

type TargetInfoGetter interface {
	// FetchRemoteTableModels obtains the models of all tables given the schema
	// name. The returned table info does not need to be precise if the encoder,
	// is not requiring them, but must at least fill in the following fields for
	// TablesFromMeta to succeed:
	//  - Name
	//  - State (must be model.StatePublic)
	//  - ID
	//  - Columns
	//     * Name
	//     * State (must be model.StatePublic)
	//     * Offset (must be 0, 1, 2, ...)
	//  - PKIsHandle (true = do not generate _tidb_rowid)
	FetchRemoteTableModels(ctx context.Context, schemaName string) ([]*model.TableInfo, error)

	// CheckRequirements performs the check whether the backend satisfies the version requirements
	CheckRequirements(ctx context.Context, checkCtx *CheckCtx) error
}

TargetInfoGetter defines the interfaces to get target information.