The PostgreSQL shared memory system is a crucial component of its scalability, with memory management being the second most important factor after CPU management. The postmaster process allocates all requested physical memory in one lump, but the operating system may not provide this contiguous block of memory due to "overcommit" policies, which can lead to inefficiencies. To optimize shared memory usage, disabling overcommit and setting the `huge_pages` parameter can significantly improve performance. Additionally, configuring the `shared_buffers` setting, which controls the amount of memory PostgreSQL requests at startup, is also essential for optimizing memory management. The article concludes by recommending Timescale Cloud, a managed service that offers extra features for time-series data, including continuous aggregation, compression, and automatic retention policies.