The clearDB service is not compatible with bluemix due to their concurrent connection limitations. With one PHP application, utilizing persistent connections, we consistently saw 4 (max) connections to clearDB, and often times our app would not be able to connect to the server. Additionally, clearDB did not give us any way to easily upgrade our service, nor did the system provide us with any useful data on the current connections. The clearDB service is also painfully slow.
Much better alternatives exist out there - even today I ran across an implementation using bluemix, maybe? I didn't read into it.
Although amazon doesn't offer a free service, their paid services are far superior to clearDB, hosting your own mysql server is also MUCH cheaper, faster, etc. I found it very difficult to find information on services that are compatible with bluemix (allowing several concurrent connections), and ultimately had to do hours of research between different platforms before finally deciding to migrate to Amazon.
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