Add PostgreSQL to your application

Add PostgreSQL to your application

To add a PostgreSQL group (instance) to your application:

  1. Open the application from the Dashboard.
  2. Click on Data Sources in the left-hand nav
  3. Click on Add Source in the sub-nav
  4. Click the green + Add Data Source button and select PostgreSQL
  5. A drawer will open from the left, with configuration options for the server.
  6. Click Add Server to start the process

Managing users in PostgreSQL

Whenever a database user creates any object (e.g. a table) in PostgreSQL, that user becomes the owner of that object. From then on, only that user or a superuser can edit or delete that object.

As such, if you delete a user from any logical PostgreSQL database managed by Cloud 66, we will automatically reassign any objects owned by that user to the default superuser named postgres that exists on all instances of Postgres.

If you need to add custom users to a Postgres database group, follow this guide on the subject.

Replicating data between PostgreSQL versions

When you initiate replication between two PostgreSQL databases on Cloud 66, we setup streaming replication between the master and replica servers. Streaming replication is based on log shipping between servers, which generally isn't possible between two servers running vastly different versions of PostgreSQL.

As such, we cannot establish replication between servers running different major release levels (e.g. 8.4 and 9.3). Though running replication between different minor release levels (e.g. 9.3 and 9.4) should work (because PostgreSQL has a policy not to make changes to disk formats between minor releases), there are also cases where this won't work.

For example, if you setup replication between a master (on 9.3) and a replica (9.4), you may see this error on the replica server:

FATAL:  database files are incompatible with server
DETAIL:  The data directory was initialized by PostgreSQL version 9.3, which is not compatible with this version 9.4.x.

In this case, you need to upgrade the data and libraries of the master server (9.3) with pg_upgrade before starting the replication.

Remember that you can set the version of PostgreSQL to install for your application by using a manifest file, like so:

            version: 9.3.6

Changing the PostgreSQL data directory

We use the default data folder when installing PostgreSQL on your server, which is /usr/local/pgsql/data. To change this folder, follow the instructions below.

1; Connect to your servers via SSH.

2; Stop the PostgreSQL service by issuing the following command:

$ (sudo -u postgres pg_ctl stop -D /usr/local/pgsql/data -m i -t 5 || true) && sudo stop postgresql 

3; Make sure that PostgreSQL is no longer running:

$ ps aux | grep pgsql

This command must not return any running PostgreSQL processes.

4; Make a new directory for your data:

$ mkdir /new/path/folder

5; Make sure that your new folder is only accessible by the PostgreSQL user:

$ chown postgres /new/path/folder
$ chmod 700 /new/path/folder

6; Move your data from the old folder to new one:

$ mv /usr/local/pgsql/data /new/path/folder

7; Create a symlink to your new folder from the old one:

$ ln -s /new/path/folder/data /usr/local/pgsql/data

8; Start the PostgreSQL service again:

$ sudo start postgresql

Your PostgreSQL service should now be working with new data folder.

Sharing databases between applications