To run postgres database server on Cygwin, you need first run the cygserver. If not, you will get error similar to this:

export PGDATA=/cygdrive/c/Users/zemian/my-pgdata
pg_ctl init
...
running bootstrap script ... FATAL:  could not create shared memory segment: Function not implemented
DETAIL:  Failed system call was shmget(key=1, size=56, 03600).
child process exited with exit code 1
initdb: removing contents of data directory "/cygdrive/c/Users/zemian/my-pgdata"
pg_ctl: database system initialization failed

To resolve this, you first start cygserver. Even if you do not have admin rights to install as Windows service, you can still run it per shell session. This is needed for shared memory need.

# For the first time, you need config
/usr/bin/cygserver-config

# Now run it
cygserver &

After above then you can start postgres

pg_ctrl init
pg_ctrl start

Postgres Windows Installation

The official download is provided by EnterpriseDB (EDB) You can get a zip package from:

https://www.enterprisedb.com/download-postgresql-binaries

To install, just unzip it.

mkdir $HOME/apps/postgresql-10.3-2
cd $HOME/apps/postgresql-10.3-2
unzip postgresql-10.3-2-windows-x64-binaries.zip

Server can be started manually like this in cmd.exe prompt:

bin\pg_ctl -D data -o "--encoding=UTF8 --auth=trust" initdb
mkdir logs
bin\pg_ctl -D data -l logs\postgres.log start

bin\createdb %USERNAME%
chcp 1252
bin\psql

zemian=# select version();
                          version
------------------------------------------------------------
 PostgreSQL 10.3, compiled by Visual C++ build 1800, 64-bit
(1 row)

By default inidb will create a "postgres" database, but user is your Windows login name, and it will not match. It’s more convient to create a database that match your username, and use that as default.

You should be careful with "--auth=trust", which can get you started quickly but not very secure.

Starting postgres server on Cygwin

Postgres Windows Installation