In which region is my database actually created?
I am using a PostgreSQL database in a web application deployed on United Kingdom bluemix region (eu-gb.bluemix.net). I chose the UK region just because it is the nearest to the customer.
My question is where my database will be actually hosted, as a single page request from the user may result in several SQL queries. I tried "Compose for PostgreSQL" and "ElephantSQL" (a third-party PostreSQL with size limit of only 20MB for the free plan) services. I think (based on the host ip) that ElephantSQL deploys the database in the same region where I created my space but Compose is always hosted in US.
Do I have any control on where my database is created?
For Compose it depends on the account creating the services.
All Bluemix accounts using an IBM email address will deploy to an IBM sandbox in US Dallas regardless of the Bluemix region used.
Bluemix public will deploy to the relevant datacenter for the Bluemix region. You can see a list of the Softlayer datacenters on the Compose support site.
Thanks @SimonHeywood for this information, Therefore I'd better move the application to the US South region.