| A quick scan of the postgresql manual turns up nothing. I would have expected the steps performed during startup recovery to be documented there. Neither is the manual explicit about data file usage for an unlogged table, there's just these two snippets: from https://www.postgresql.org/docs/15/sql-createtable.html#SQL-...: > Data written to unlogged tables is not written to the write-ahead log (see Chapter 30), which makes them considerably faster than ordinary tables and from https://www.postgresql.org/docs/15/glossary.html#GLOSSARY-UN...: > The property of certain relations that the changes to them are not reflected in the WAL. This disables replication and crash recovery for these relations. Which both say nothing about the normal data files underlying unlogged tables, so none of what I wrote can be found in the official docs (or maybe it can, just not by me ;) However, there is also this page from the postgres developer wiki: https://wiki.postgresql.org/wiki/Future_of_storage which does say that pure in-memory tables are not supported by Postgres: > it would be nice to have in-memory tables if they would perform faster. Somebody could object that PostgreSQL is on-disk database which shouldn't utilize in-memory storage. But users would be interested in such storage engine if it would give serious performance advantages. |