> [!LogicalRewriteTruncate] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_io_logicalrewritetruncate.png"></td><td><b>Wait Category</b></td><td>IO</td></tr><tr><td><b>Mechanism</b></td><td><code>LogicalRewrite</code></td></tr><tr><td><b>Operations</b></td><td><a href="Operations/Table/SeqScan">SeqScan</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>Metadata Cleanup Barrier</b>. To prevent the <code>pg_logical/mappings/</code> directory from growing indefinitely, Postgres must physically remove mapping segments once all active replication slots have successfully consumed the associated transactions.</td></tr></table>