Export only new data since the last PostgreSQL database export

Question

I have a decent sized PostgreSQL database (approx 6GB & growing). A full backup/export of the database is done every few hours via cron & pg_dump. Specifically, can I export only the changes to the database since the last export? Or perhaps run a utility that compares the two exports and appends the differences to the original, etc? I'm trying to save disk space and "cloud" transfer time.

Answer 1

No, you can't. What you could do, is setting up WAL archiving to make incremental backups: http://www.postgresql.org/docs/current/static/continuous-archiving.html#BACKUP-ARCHIVING-WAL

This can only be done for the whole cluster, not for a single database.

Answer 2

Use differential backup solution, like for example free Duplicity.

But remember to store a database dump - don't store live database files, as your backup will be corrupted.