Multiple instances are running on same port 5432

[Payal]

I installed postgresql-9.3 from ubuntu package with apt-get.

I also installed postgresql9.6rc1 from source.

when I bring up packaged install first and then try to bring up the source install, source install errors out saying that the socket file .s.PGSQL.5432 already exists and postmaster is already running, which is expected.

But when I bring up source install first, then package install with service like sudo /etc/init.d/postgresql start, it starts right up on port 5432

root@ip-10-181-183-93:/home/ubuntu# netstat -nlp | grep 5432
tcp 0 0 127.0.0.1:5432 0.0.0.0:* LISTEN 4552/postgres
tcp6 0 0 :::5432 :::* LISTEN 4744/postgres
unix 2 [ ACC ] STREAM LISTENING 84618 4744/postgres /var/run/postgresql/.s.PGSQL.5432
unix 2 [ ACC ] STREAM LISTENING 83803 4552/postgres /tmp/.s.PGSQL.5432

The exact process I followed is attached in the file.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: postgresql-9.3 9.3.14-0ubuntu0.14.04
ProcVersionSignature: User Name 3.13.0-48.80-generic 3.13.11-ckt16
Uname: Linux 3.13.0-48-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.8
Architecture: amd64
Date: Wed Sep 14 22:45:46 2016
Ec2AMI: ami-d85e75b0
Ec2AMIManifest: (unknown)
Ec2AvailabilityZone: us-east-1e
Ec2InstanceType: m1.small
Ec2Kernel: aki-919dcaf8
Ec2Ramdisk: unavailable
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: postgresql-9.3
UpgradeStatus: No upgrade log present (probably fresh install)