Richard Huxton <dev@archonet.com> writes:
>> First try was using a file system copy to reduce downtime as it was two
>> same 7.4.x version but the result was not working (maybe related to
>> architecture change 32bits => 64 bits) so I finally dropped the db and
>> performed an dump/restore. I think, the db was a mix of 32/64 bits files.
> Ah! That'll do it. You will get problems with a filesystem copy if
> 1. The database is running.
> 2. The architectures aren't identical
> 3. The installation options are different (a simple date option
> difference can cause problems)
PG 8.1 and later record MAXALIGN in pg_control.h, and will refuse to
start up if there is a 32/64 bit compatibility problem. But 7.4 has
no such defense. It does check for --enable-integer-datetimes
compatibility, though.
regards, tom lane