AWSでPSQLが入っていなかったのでyumインストール。

結論としては特にはまるポイントもなく通常通りでいけた。

（青字が入力）

$yum search postgresql
Loaded plugins: priorities, update-motd, upgrade-helper
================================================================= N/S matched: postgresql ==================================================================
（中略）
postgresql92.x86_64 : PostgreSQL client programs
postgresql92-contrib.x86_64 : Extension modules distributed with PostgreSQL
postgresql92-devel.x86_64 : PostgreSQL development header files and libraries
postgresql92-docs.x86_64 : Extra documentation for PostgreSQL
postgresql92-libs.i686 : The shared libraries required for any PostgreSQL clients
postgresql92-libs.x86_64 : The shared libraries required for any PostgreSQL clients
postgresql92-plperl.x86_64 : The Perl procedural language for PostgreSQL
postgresql92-plpython26.x86_64 : The Python2 procedural language for PostgreSQL
postgresql92-plpython27.x86_64 : The Python3 procedural language for PostgreSQL
postgresql92-pltcl.x86_64 : The Tcl procedural language for PostgreSQL
postgresql92-server.x86_64 : The programs needed to create and run a PostgreSQL server
postgresql92-server-compat.x86_64 : PostgreSQL server config files for backward compatibility
postgresql92-test.x86_64 : The test suite distributed with PostgreSQL
postgresql93.x86_64 : PostgreSQL client programs
postgresql93-contrib.x86_64 : Extension modules distributed with PostgreSQL
（中略）

Name and summary matches only, use “search all” for everything.

家の環境の最新クライアント（psql）がpostgresql93.x86_64ぽいので確認

$ yum info postgresql93.x86_64
Loaded plugins: priorities, update-motd, upgrade-helper
Available Packages
Name : postgresql93
Arch : x86_64
Version : 9.3.9
Release : 1.58.amzn1
Size : 4.2 M
Repo : amzn-updates/2015.03
Summary : PostgreSQL client programs
URL : http://www.postgresql.org/
License : PostgreSQL
Description : PostgreSQL is an advanced Object-Relational database management system (DBMS).
: The base postgresql package contains the client programs that you’ll need to
: access a PostgreSQL DBMS server, as well as HTML documentation for the whole
: system. These client programs can be located on the same machine as the
: PostgreSQL server, or on a remote machine that accesses a PostgreSQL server
: over a network connection. The PostgreSQL server can be found in the
: postgresql-server sub-package.

あっていたのでインストール

$ sudo yum install postgresql93.x86_64

（中略）

Complete!

$ psql -h ホスト名 -U ユーザ名 -d DB名

つながった。