Yes, in many cases (until I stopped using it), it messed up my benchmarks. I was testing some queries, and often it was:
- pgserver fast, returns 10000 rows, pgcli takes time to parse -> result: total time 10s
- pgserver slow, returns 1 row, pgcli instant -> result: total time 10 sec.
As we are working in efficient C/C++, our internal time to parse the query set is closer to psql than pgcli, so we tend to prefer the pgserver fast, but the benchmark using pgcli did not clearly show the best time.
Also, when you are testing a query on one machine, you have to carefully monitor the CPU usage to differentiate the CPU pegging by postgres from the one by pgcli.
All those issues were gone when I got back to standard psql.