forking-and-retracing.md

Forking & Retracing

During the lifetime of a program, Tuner will record every step that a ConfigurableCorePool went through in memory. With an id of PoolState, you can let the pool recover to that state.

// current state: foo
let poolStateId: string = configurableCorePool.getPoolState().id;

// some transactions...
// current state: bar

configurableCorePool.recover(poolStateId);
// current state: foo

Or just let the pool step back to last state.

// current state: foo
let poolStateId: string = configurableCorePool.getPoolState().id;

// one transaction...
// current state: bar

configurableCorePool.stepBack();
// current state: foo

Sometime we want multiple instances to try out various of possibilities from current state, it's good time using fork to do that.

let forkedConfigurableCorePool: ConfigurableCorePool =
  configurableCorePool.fork();

// some transactions with configurableCorePool...

// some transactions with forkedConfigurableCorePool...

The forked pool will remain the same state as its parent and the two pools act independently.

Note: poolState.fromTransition of a pool built from a PoolConfig or recovered from a snapshot will be undefined while poolState.fromTransition of a forked pool will have a Record with ActionType.FORK and its parent as source PoolState.