MySQL is needlessly slow at accepting new connections. People usually work around that by having various sorts of connection pools, but there’s always a scale at which connection pools are not feasible. Sometimes connection avalanches come unexpected, and even if MySQL would have no trouble dealing with queries, it will have problems letting clients in. Something has to be done about it.
Lots of these problems have been low hanging fruits for years – it ‘was not detected’ by benchmarks because everyone who benchmarks MySQL would know that persistent connections are much faster and therefore wouldn’t look at connection speeds anymore.
Usually …[Read more...]