Tom Lane wrote:
> Doing pg_dump would expose the mistake if you'd removed an actual
> table's files. But I'm not sure it would expose it if you removed
> an index ...
>
Right, but in theory if you screwed up and accidentally deleted a file
holding an index, you could recover from that in the possibly distant
future by rebuilding it, with some pain but no expected loss. Whereas
if you deleted some data by removing a file, you really want to know
that's what you did immediately, so you can put it back before you
forget where it all was at.
Sometimes people who have fully setup replication for backup purposes
ask me if they should continue saving pg_dump output somewhere. I think
it's reasonable to generate a dump using it periodically whether or not
you intend to save the result permanently, just as a paranoid sanity
check that you can still read everything. I don't trust disks and
filesystems that much.
(If you're reading this and feel the need to write a pro-ZFS essay at
this point, consider yourself trolled)
--
Greg Smith 2ndQuadrant US Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com www.2ndQuadrant.us