pkg/41067: time_t change from int to __int64_t breaks PostgreSQL databases

[tgen%deepbone.net@localhost]

>Number:         41067
>Category:       pkg
>Synopsis:       Change of sizeof(time_t) breaks PostgreSQL on-disk structures
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Mar 24 17:40:00 +0000 2009
>Originator:     Thomas E. Spanjaard
>Release:        NetBSD 5.99.8
>Organization:
>Environment:
System: NetBSD cassiopeia.ssr.netphreax.net 5.99.8 NetBSD 5.99.8 (CASSIOPEIA) 
#0: Sat Mar 21 19:38:06 UTC 2009 
tgen%cassiopeia.ssr.netphreax.net@localhost:/home/obj/netbsd/obj/sys/arch/amd64/compile/CASSIOPEIA
 amd64
Architecture: x86_64
Machine: amd64
>Description:
Databases created with PostgreSQL before the time_t changes are broken after
building a new PostgreSQL after the time_t changes and trying to access them.
This is because PostgreSQL uses time_t values in on-disk structures, and thus
reads in eight bytes for any time_t value instead of four before. This renders
a database inoperable:
FATAL:  incorrect checksum in control file
>How-To-Repeat:
1) Create a database on a pre-time_t changes-system;
2) Update NetBSD to post-time_t changes;
3) Compile and install a new PostgreSQL package;
4) Watch PostgreSQL die.
>Fix:
There are several possible fixes:

- Revert the time_t changes;
- Don't update NetBSD to post-time_t changes;
- Shake fist at christos and dump the database before updating (and loading
  after);
- Bug the PostgreSQL people to move to a standard on-disk format independent
  of the platform (i.e. don't store time_t values on disk, but a fixed format).