xmin value from pg_stat_replication - Mailing list pgsql-admin

All;


We have a master and a standby (Streaming replication).

This query produces a value of approx 1.5million on the master and 
approx 80million on the standby:


select slot_name, slot_type, database, xmin from pg_replication_slots 
order by age(xmin);


We are running replication in async mode.


A couple of questions:


- Is it unusual for the master & standby to differ dramatically like this?

- could the replication slot (i.e. the xmin on the standby) be 
preventing vacuum from cleaning up row versions on the master?


Thanks in advance