Re: Regarding query optimisation (select for update)

Laurenz Albe <laurenz.albe@cybertec.at> writes:
> Text is easier to read than images...

Indeed.

> Anyway, this statement was done in under a millisecond.
> I wouldn't call that slow...

It looks to me like this EXPLAIN ANALYZE was done against a totally
empty table, so probably in a freshly-set-up dev environment.  That
is not going to be helpful in identifying your production problem.
Note the caveat at [1]:

    EXPLAIN results should not be extrapolated to situations much
    different from the one you are actually testing; for example,
    results on a toy-sized table cannot be assumed to apply to large
    tables.

            regards, tom lane

[1] https://www.postgresql.org/docs/current/using-explain.html#USING-EXPLAIN-CAVEATS