OK now I really need help. I tried to install version 9.4.4-2 of
Postgres with
ftp://www.fruitbat.org/pub/cygwin/circa/2015/09/25/151012/index.html,
but now it won't start. I also tried to install 9.4.4-1 but that won't
work either. I also tried to exit all Cygwin processes and run 'dash'
and 'rebaseall', but it didn't help. How do I install an old version of
Postgres 9.4 to upgrade to 9.5?

$ /usr/sbin/postgres --version
postgres (PostgreSQL) 9.4.4

$ /usr/sbin/postgres
FATAL:  could not create shared memory segment: Function not implemented
DETAIL:  Failed system call was shmget(key=5432001, size=40, 03600).

$ /setup-x86 -X -q -P postgresql-9.4.4-1
note: Hand installation over to elevated child process.

$ /usr/sbin/postgres --version
postgres (PostgreSQL) 9.4.4

$ /usr/sbin/postgres
FATAL:  could not create shared memory segment: Function not implemented
DETAIL:  Failed system call was shmget(key=5432001, size=40, 03600).

http://stackoverflow.com/questions/36411485/how-do-i-install-postgres-9-4-on-cygwin


On 4/4/2016 3:19 PM, Chloe wrote:
> Can you please change the Postgres packages to use postgres94,
> postgres95, postgres96, etc. names? Each version is incompatible with
> the previous. This will allow installing Postgres in separate binary
> directories to enable upgrades. Alternatively, please increase the
> 'previous version' history to allow installing old versions. Setup
> only has 1 previous version, and if the current version is 9.5.2 and
> the previous version is 9.5.1, then there is no way (or very
> difficult) to install 9.4!
>
> http://serverfault.com/questions/532379/how-do-i-upgrade-postgres-database-in-cygwin
>