postgresql - How Postgres achieves database-level isolation -


per doc of postgres,

databases physically separated , access control managed @ connection level.

is there further details how postgres achieves physical isolation? files used store data in backend totally separate?

is there further details how postgres archives physical isolation? files used store data in backend totally separate?

yes. each table stored separate file (actually, multiple files). different databases in different directories. indexes, etc in 1 or more separate files.

however, there's lot of shared state. system tables shared between databases. write-ahead log (wal) shared, commit log (pg_clog). cannot extract 1 database's files , attach postgresql instance. they're meaningless without of shared files.


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