What does this implement/fix?

Improve query storing algorithm to better cope with bursts of queries of arbitrary size and frequency. See related Discourse bug chasing for further details.

This is overall an improvement as the new strategy guarantees that no queries can be lost on one hand and drastically reduces the workload on the other hand by using persistent prepared statements instead of compiling them once per second.

Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

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