Should a database be cleared before restoration?

[jfmays]

I have a dumpfile created with pg_dumpall. If I need to restore a database from it to bring it up to date with another database system, do I need to clear out the contents of the database first? I don't want to create duplicate records by pulling in the dumpfile.

[rski]

I did not use postgres for a very long time but as far as I remember if you do not use -F then the dump will be sql text file. You can check if the dump contains drop table statements before creating table from dump (I think tables are dropped before recreating).