> [!SLRUFlushSync] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_io_slruflushsync.png"></td><td><b>Wait Category</b></td><td>IO</td></tr><tr><td><b>Mechanism</b></td><td><code>SLRU</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>Global Metadata Durability Barrier</b>. SLRU is the specialized storage engine Postgres uses for non-relation metadata that requires strict transactionality, such as the Transaction Status (Xact), MultiXact, and Subtransaction logs.</td></tr></table>