Fun fact, the overhead for a DB query (not including the network latency) is about 250 microseconds (or 0.25ms). And a typical DB kernel can do at least 16MB/core second of throughput. So that 30ms query I would expect is scanning several GB of data to find its results. Try doing that yourself and your latency would probably grow into seconds. Systems programming is hard...

PS moving from stateful processing to something with a distributed cache is moving from RAM to network. That's at least a 10x drop off in throughput.