Search for huge pages in the documentation of a DBMS that implements its own caching in shared memory: Oracle [1], PostgreSQL [2], MySQL [3], etc. When you're

Search for huge pages in the documentation of a DBMS that implements its own caching in shared memory: Oracle [1], PostgreSQL [2], MySQL [3], etc. When you're caching hundreds of gigabytes, it makes a difference. Here's a benchmark comparing PostgreSQL performance with regular, large, and huge pages [4]. There was a really bad performance regression in Linux a couple of years ago that killed performance with large memory regions like this (can't find a useful link at the moment), and the short-term mitigation was to increase the huge page size from 2MB to 1GB. [1] https://blogs.oracle.com/exadata/post/huge-pages-in-the-context-of-exadata https://blogs.oracle.com/exadata/post/huge-pages-in-the-cont... [2] https://www.postgresql.org/docs/current/kernel-resources.html#LINUX-HUGE-PAGES https://www.postgresql.org/docs/current/kernel-resources.htm... [3] https://dev.mysql.com/doc/refman/8.4/en/large-page-support.html https://dev.mysql.com/doc/refman/8.4/en/large-page-support.h... [4] https://www.percona.com/blog/benchmark-postgresql-with-linux-hugepages/ https://www.percona.com/blog/benchmark-postgresql-with-linux...