Trouble installing Gitlab on CentOS 6.5 - postgresql

Question

I have attempted, several times to install Gitlab on my CentOS 6.5 VPS as per the instructions on the Official page and every time, it fails during the "gitlab-ctl reconfigure" stage of installation. I tried googling around and looking in other questions on here without much luck.
Error is as follows:
* execute[create gitlab database user] action run
================================================================================
Error executing action `run` on resource 'execute[create gitlab database user]'
================================================================================
---- Begin output of /opt/gitlab/embedded/bin/psql --port 5432 -d template1 -c "CREATE USER gitlab" ----
STDOUT:
STDERR: psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/tmp/.s.PGSQL.5432"?
---- End output of /opt/gitlab/embedded/bin/psql --port 5432 -d template1 -c "CREATE USER gitlab" ----

Answer 1

This might not be immediately related to GitLab, but to PostgreSQL itself.
See "Chapter 17. Server Setup and Operation", section "Client Connection Problems":
Alternatively, you'll get this when attempting Unix-domain socket communication to a local server:
psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/tmp/.s.PGSQL.5432"?
The last line is useful in verifying that the client is trying to connect to the right place.
If there is in fact no server running there, the kernel error message will typically be either Connection refused or No such file or directory, as illustrated.
(It is important to realize that Connection refused in this context does not mean that the server got your connection request and rejected it. That case will produce a different message, as shown in Section 19.4.)
Other error messages such as Connection timed out might indicate more fundamental problems, like lack of network connectivity.
So make sure the database can start first.
The OP Luke Usher confirms in the comments:
The default PostgreSQL config included in gitlab was set to allocate more memory for shared_buffer than I have available.
This was corrected by adding postgresql['shared_buffers'] = "1024MB" to /etc/gitlab/gitlab.rb.