sys.filesys_number_from_rowid

Given a row, return its file system location (its SSD).
sys.filesys_number_from_rowid(rowid)

See Querying Row IDs.

This function accepts either the string rowid as its input or a specific rowid value. In most cases you will use the string rowid to return the specific row ID for each row in a set of rows. (If you specify an individual row ID as the input to the function, make sure it is valid; the system does not detect row IDs that are not valid or do not exist.)

For example:
yellowbrick_test=# select distinct sys.filesys_number_from_rowid(rowid) 
from matchstats order by 1;
 filesys_number_from_rowid 
---------------------------
                         0
                         1
                         4
                         5
                         6
                         7
(6 rows)
premdb=# select rowid, sys.filesys_number_from_rowid(rowid) from match order by 1 limit 5;
      rowid       | filesys_number_from_rowid 
------------------+---------------------------
 5630521744818176 |                         5
 5630521744818177 |                         5
 5630521744818178 |                         5
 5630521744818179 |                         5
 5630521744818180 |                         5
(5 rows)
premdb=# select sys.filesys_number_from_rowid(5630521744818176) from match limit 1;
 filesys_number_from_rowid 
---------------------------
                         5
(1 row)