Postgres: Missing data after Binary Copy - Is VACUUM FULL required? I'm running Postgres 9.0 on a relatively big (10TB) and old Database. I must move that database to new server hardware, so I copied the whole $PGDATA directory via rsync of a LVM Snapshot and used archive/restore Commands to get all the changes after the copy process. I switched to the new server using the trigger_file.

Everything looked good so far, but after a few hours I'm having some tables where data is not showing up in SELECTs (I think that was instant after copying, but have no evidence).

I did ANALYZE and VACUUM on the table - no data there. But when I do a VACUUM FULL on the table, the data appears.

I couldn't find anything comparable in the postgres documentation except the Transaction Id wraparound. The autovacuum was disabled for 1/2 year at the old server.

A week ago I activated it and autovacuum did its job as I saw.

On the old database server, the data from my test table is is returned by SELECTs.

Did anyone encounter such a problem? I'm looking for a query that can show me which of the tables needs such a vacuum full. 

Why cannot I copy the data directory at the file system level is also hard to understand for me at the moment. Did I miss anything from the documentation that needs to be done after using the Trigger File?

I don't think it's relevant, but the version at the old server was 9.0.18 and at the new one 9.0.23.
To answer myself. 

It was somehow related to  https://www.postgresql.org/message-id/flat/111D0E27-A8F3-4A84-A4E0-B0FB703863DF%40s24.com#111D0E27-A8F3-4A84-A4E0-B0FB703863DF@s24.com i think.

The OS changed from Debian7 to Debian8, and so the dynamically linked libc6 changed. 
Had to do a REINDEX on all my Tables with Indexed String Columns.