That's mostly false for a nontrivial fraction of queries in most bigger projects. If your queries are doing sane things (not regularly full table scanning for each customer, ...), little things like datetime conversions as the rows are instantiated in Python easily dwarf the cost of the database (depending on your networking setup and exact queries, perhaps just in throughput instead of latency, but Python will the still at least be the "cost" bottleneck for your app).
Yes!! I recently found a 12% overall latency win (_much_ higher in just the datetime code I changed) at $WORK replacing some of the native datetime conversions with something more intelligent, tailored to the specific <redacted work stuff> context at hand.
