> [!Extension] > <table><tr><td rowspan="4" width="25%"><img src="assets/wl_extension_extension.png"></td><td><b>Wait Category</b></td><td>Extension</td></tr><tr><td><b>Mechanism</b></td><td><code>ExtensionWaitEvent</code></td></tr><tr><td><b>Operations</b></td><td><a href="Operations/Other/FunctionScan">FunctionScan</a></td></tr><tr><td><b>Resources</b></td><td><a href="Resources/CPU">CPU</a>, <a href="Resources/RAM">Memory</a></td></tr><tr><td colspan="3">This wait event serves as a <b>generic category</b> for synchronization logic implemented within third-party extensions (such as PostGIS, TimescaleDB, or pgvector). Because the core engine does not have visibility into the internal states of these modules, it categorizes any custom-defined stall under the broad <code>Extension</code> wait class.</td></tr></table>