> [!WALInitSync] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_io_walinitsync.png"></td><td><b>Wait Category</b></td><td>IO</td></tr><tr><td><b>Mechanism</b></td><td><code>pg_wal</code></td></tr><tr><td><b>Operations</b></td><td><a href="Operations/Distributed/Redistribute">Redistribute</a></td></tr><tr><td><b>Resources</b></td><td><a href="Resources/disk IO">disk IO</a>, <a href="Resources/CPU">CPU</a></td></tr><tr><td colspan="3"><b>Log Provisioning Durability Barrier</b>. To ensure that a crash during a write doesn't leave the transaction log in an unrecoverable state, Postgres must guarantee that the space for a new WAL segment is physically allocated and zeroed on the disk before it can be used.</td></tr></table>