migration

Documentation

Overview

Package migration contains the logic for running online schema changes.

Index

• Variables
• type CutOver
  • func NewCutOver(db *sql.DB, table, newTable *table.TableInfo, oldTableName string, ...) (*CutOver, error)
  • func (c *CutOver) Run(ctx context.Context) error
• type Migration
  • func (m *Migration) Run() error
• type Progress
• type Runner
  • func NewRunner(m *Migration) (*Runner, error)
  • func (r *Runner) Close() error
  • func (r *Runner) GetProgress() Progress
  • func (r *Runner) Run(originalCtx context.Context) error
  • func (r *Runner) SetLogger(logger loggers.Advanced)
  • func (r *Runner) SetMetricsSink(sink metrics.Sink)

Variables

var (
	ErrMismatchedAlter = errors.New("alter statement in checkpoint table does not match the alter statement specified here")
)

Types

type CutOver

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

func NewCutOver

func NewCutOver(db *sql.DB, table, newTable *table.TableInfo, oldTableName string, feed *repl.Client, dbConfig *dbconn.DBConfig, logger loggers.Advanced) (*CutOver, error)

NewCutOver contains the logic to perform the final cut over. It requires the original table, new table, and a replication feed which is used to ensure consistency before the cut over.

func (*CutOver) Run

func (c *CutOver) Run(ctx context.Context) error

type Migration

type Migration struct {
	Host                 string        `name:"host" help:"Hostname" optional:"" default:"127.0.0.1:3306"`
	Username             string        `name:"username" help:"User" optional:"" default:"msandbox"`
	Password             string        `name:"password" help:"Password" optional:"" default:"msandbox"`
	Database             string        `name:"database" help:"Database" optional:"" default:"test"`
	Table                string        `name:"table" help:"Table" optional:"" default:"stock"`
	Alter                string        `name:"alter" help:"The alter statement to run on the table" optional:"" default:"engine=innodb"`
	Threads              int           `name:"threads" help:"Number of concurrent threads for copy and checksum tasks" optional:"" default:"4"`
	TargetChunkTime      time.Duration `name:"target-chunk-time" help:"The target copy time for each chunk" optional:"" default:"500ms"`
	ForceInplace         bool          `` /* 135-byte string literal not displayed */
	Checksum             bool          `name:"checksum" help:"Checksum new table before final cut-over" optional:"" default:"true"`
	ReplicaDSN           string        `name:"replica-dsn" help:"A DSN for a replica which (if specified) will be used for lag checking." optional:""`
	ReplicaMaxLag        time.Duration `` /* 127-byte string literal not displayed */
	LockWaitTimeout      time.Duration `name:"lock-wait-timeout" help:"The DDL lock_wait_timeout required for checksum and cutover" optional:"" default:"30s"`
	SkipDropAfterCutover bool          `name:"skip-drop-after-cutover" help:"Keep old table after completing cutover" optional:"" default:"false"`
	DeferCutOver         bool          `name:"defer-cutover" help:"Defer cutover (and checksum) until sentinel table is dropped" optional:"" default:"false"`
	Strict               bool          `name:"strict" help:"Exit on --alter mismatch when incomplete migration is detected" optional:"" default:"false"`
}

func (*Migration) Run

func (m *Migration) Run() error

type Progress

type Progress struct {
	CurrentState string // string of current state, i.e. copyRows
	Summary      string // text based representation, i.e. "12.5% copyRows ETA 1h 30m"
}

Progress is returned as a struct because we may add more to it later. It is designed for wrappers (like a GUI) to be able to summarize the current status without parsing log output.

type Runner

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

func NewRunner

func NewRunner(m *Migration) (*Runner, error)

func (*Runner) Close

func (r *Runner) Close() error

func (*Runner) GetProgress

func (r *Runner) GetProgress() Progress

func (*Runner) Run

func (r *Runner) Run(originalCtx context.Context) error

func (*Runner) SetLogger

func (r *Runner) SetLogger(logger loggers.Advanced)

func (*Runner) SetMetricsSink

func (r *Runner) SetMetricsSink(sink metrics.Sink)