Question: I just got a new mac and am getting everything installed on it (postgres, postgis, qgis, grass, gdal, brew, ruby, etc) and am about to install QGis.

QGis is a great tool for me, except for that with my other mac I was never able to get it to connect to PostgreSQL.

PGAdmin always worked when connecting, but connecting QGis to the Postgres.app implementation of Postgresql never was able to connect. The error messages were depressingly vague (just recreated): `Connection failed - Check settings and try again.`

So my question is this. What are the ideal settings that allow qgis to connect easily to postgresql? I've found Postgres.app an easy to use implementation, but should I abandon it and use the normal brew-installed postgresql instead to get qgis to connect?

Or even better, is there a qgis/postgresql co-installation somewhere that would come close to guaranteeing inter-functionality between these two systems?

UPDATE:
(after temporarily removing the Postgres.app PostgreSQL implementation)
When I run this command:

```
brew install qgis --with-grass --with-postgis

```

brew starts off by installing postgresql. I'm going with this for now and am hoping the "pipes" between QGis & PostgreSQL will be setup to communicate with one another...

Answer: 
I think the true goal of this question (mine) was to use qgis in conjunction with a database. So my solution here, having not been able to get PostgreSQL to work for me here, is to simply convert my PostgreSQL PostGIS database into a spatialite database, and load that into QGIS.

There will be some performance issues with spatialite, but given PostgreSQL and no other SQL database working for me with QGis? spatialite will be just fine.
last time i have same problem :

what i have done to solve that is refer on this link <http://hub.qgis.org/issues/735>
i hope can solve your problem to.

the problem is because postgres still limit connection. if you have add configuration for truth the localhost for connection to database everything running smooth.

Other thing you must consider after have connection is to activate the PostGIS extension.
Happy Mapping.