# Write-Ahead Log (WAL)

![Chapter Overview](./lsm-tutorial/week2-06-overview.svg)

In this chapter, you will:

* Implement encoding and decoding of the write-ahead log file.
* Recover memtables from the WALs when the system restarts.

## Task 1: WAL Encoding

## Task 2: Write WALs

## Task 3: Recover from the WALs

## Test Your Understanding

* When can you tell the user that their modifications (put/delete) have been persisted?

We do not provide reference answers to the questions, and feel free to discuss about them in the Discord community.

{{#include copyright.md}}