Seems a really bad study, since it doesn't mention the exact methodology (caching, exact queries, size of the JSON data, etc.), nor does it attempt to figure ou

Seems a really bad study, since it doesn't mention the exact methodology (caching, exact queries, size of the JSON data, etc.), nor does it attempt to figure out why PostgreSQL is taking 8 ms to do something that should take much less and why reads and writes take the same time, or why Redis is taking 0.5 ms (i.e. millions of CPU cycles) for something that should essentially just do a memcpy.