backend

package
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 Go to latest Published: Dec 10, 2024 License: Apache-2.0 Imports: 14 Imported by: 0

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Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func MakeUUID 

func MakeUUID(tableName string, engineID int64) (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
	// local backend external engine specified configuration
	External *ExternalEngineConfig
	// KeepSortDir indicates whether to keep the temporary sort directory
	// when opening the engine, instead of removing it.
	KeepSortDir bool
	// TS is the preset timestamp of data in the engine. When it's 0, the used TS
	// will be set lazily. This is used by local backend. This field will be written
	// to engineMeta.TS and take effect in below cases:
	// - engineManager.openEngine
	// - engineManager.closeEngine only for an external engine
	TS uint64
}

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 ExternalEngineConfig 

type ExternalEngineConfig struct {
	StorageURI string
	DataFiles  []string
	StatFiles  []string
	StartKey   []byte
	EndKey     []byte
	JobKeys    [][]byte
	SplitKeys  [][]byte
	// TotalFileSize can be an estimated value.
	TotalFileSize int64
	// TotalKVCount can be an estimated value.
	TotalKVCount int64
	CheckHotspot bool
}

ExternalEngineConfig is the configuration used for local backend external 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

	// blocksize
	BlockSize int
}

LocalEngineConfig is the configuration used for local backend in OpenEngine.

type LocalWriterConfig 

type LocalWriterConfig struct {
	// Local backend specified configuration
	Local struct {
		// is the chunk KV written to this LocalWriter sent in order
		IsKVSorted bool
		// MemCacheSize specifies the estimated memory cache limit used by this local
		// writer. It has higher priority than BackendConfig.LocalWriterMemCacheSize if
		// set.
		MemCacheSize int64
	}
	// TiDB backend specified configuration
	TiDB struct {
		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 {
	// FetchRemoteDBModels obtains the models of all databases. Currently, only
	// the database name is filled.
	FetchRemoteDBModels(ctx context.Context) ([]*model.DBInfo, error)

	// FetchRemoteTableModels obtains the TableInfo of given tables under the schema
	// name. It returns a map whose key is the table name in lower case and value is
	// the TableInfo. If the table does not exist, it will not be included in the
	// map.
	//
	// 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, tableNames []string) (map[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.

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