Hi, On 2021-08-09 18:58:53 -0500, Justin Pryzby wrote: > Define shared_buffers as the exact size to be allocated/requested from the OS > (regardless of whether they're huge pages or not), and have postgres compute > everything else based on that. So shared_buffers=2GB would end up being > 1950MB > (or so) of buffer cache. We'd have to check that after the other allocations, > there's still at least 128kB left for the buffer cache. Maybe we'd have to > bump the minimum value of shared_buffers.
I don't like that. How much "other" shared memory we're going to need is very hard to predict and depends on extensions, configuration options like max_locks_per_transaction, max_connections to a significant degree. This way the user ends up needing to guess at least as much as before to get to a sensible shared_buffers. Greetings, Andres Freund
