Queries-Per-Hour Limits Removed From Azure Cloud

Effective immediately, ClearDB is removing the queries per hour (QPH) limits imposed on all multitenant databases provisioned in the Windows Azure cloud.

Most of our customers may not even realize that we had such a limitation. We originally implemented it as an abuse management tool, in order to prevent customers from using a disproportionate share of resources on our multitenant clusters and possibly negatively impacting other users.

As it turns out, the version of the mysql server software we had been using on our Azure cluster nodes contained a bug that prevented those QPH limits from being rigorously enforced. We found that out this past week when we upgraded to a version where the bug had been squashed. We immediately began hearing from customers who were temporarily losing access to their databases because their normal operations were exceeding the QPH limit for their service plan.

After carefully evaluating the situation we came to the following conclusions:

  • One of the more popular applications within Azure is a WordPress blog. And some popular WordPress plugins are so inefficient in their db usage that they can easily and repeatedly exceed the QPH limit
  • Even though only a small percentage of our customers were affected, and even though the change was nothing more than holding them to our Terms of Service, we decided it was unfair to impose a hard limit which previously, due to the server bug, they had not been subject to.
  • The QPH limits were established to prevent abuse. But despite the bug, we have never had widespread difficulty with customers “hogging” resources. Our systems are powerful enough to handle pretty much any non-hostile use case. So the QPH limits were a solution to a problem which now turns out to be practically nonexistent.

Therefore, we decided that the QPH limits were providing no real benefit to either ClearDB or our customers, and we have removed them.

We wish to extend our apologies for what was an annoying and stressful few days to those customers who were affected by this situation. You, our customers, are ultimately responsible for ClearDB’s success, and we hope with this change we will continue to serve your needs well and deserve your continued support.