> [!SerialBuffer] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_lw_serialbuffer.png"></td><td><b>Wait Category</b></td><td>LWLock</td></tr><tr><td><b>Mechanism</b></td><td><code>SSI</code></td></tr><tr><td><b>Operations</b></td><td><a href="Operations/Table/SeqScan">SeqScan</a>, <a href="Operations/Index/IndexScan">IndexScan</a></td></tr><tr><td><b>Resources</b></td><td><a href="Resources/RAM">Memory</a>, <a href="Resources/CPU">CPU</a></td></tr><tr><td colspan="3"><b>Serializable Metadata Access Bottleneck</b>. The serial log (stored in <code>pg_serial/</code>) is used by the Serializable Snapshot Isolation (SSI) engine to track which transactions have committed and what their finished sequence number is.</td></tr></table>