>> Query returned successfully with no result in 600 ms.
>>
>> Why SELECT takes 3+ second to execute? Is it something to do with my
>> Postgres server optimization, or PgAdmin does not show correct data
>> retrieval runtime (leaks over into query runtime or something)?
>
> Data transfer and display time usually.
>
> Try SELECT count(*) FROM ... instead and see if the times are closer.
Correct. That executes in 300ms flat:
Total query runtime: 301 ms.
Data retrieval runtime: 380 ms.
1 rows retrieved.
Peter