patch proposal

Hi,

During the recovery process, It would be nice if PostgreSQL generates an
error by aborting the recovery process (instead of starting-up the cluster)
if the intended recovery target point is not reached and give an option to
DBA to resume the recovery process from where it exactly stopped.

The issue here is, if by any chance, the required WALs are not available or
if there is any WAL missing or corrupted at the restore_command location,
then PostgreSQL recovers until the end of the last available WAL and
starts-up the cluster. At a later point-of-time, if the missing WAL is
found, then, it is not possible to resume the recovery process from where
it stopped previously. The whole backup restoration + recovery process must
be initiated from the beginning which can be time consuming especially when
recovering huge clusters sizing up to Giga bytes and Tera Bytes requiring
1000s of WALs to be copied over for recovery.

Any thoughts ? comments?

I can work on this patch based on the comments/feedback.

Regards,
Venkata B N

Fujitsu Australia