Re: How to determine which file contains which block

Frank Way <fgw_three@yahoo.com> writes:
> After finding the ctid in (block,tuple) format, how do you know which
> file in all the subdirectories under /usr/local/pgsql/data/base
> contains that block?

The subdirectories are named after the OIDs of their databases
(pg_database.oid column).  Individual files are named after the
relfilenodes of their tables/indexes (pg_class.relfilenode).
Note also that tables exceeding 1GB will be broken into gigabyte-size
segments named nnn, nnn.1, nnn.2, etc; if you are dealing with one
of these then you need to determine which segment to use from the
block number.

            regards, tom lane