Обсуждение: Can I test Extended Query in core test framework

You could run PREPARE and EXECUTE as SQL commands from psql. Please
take a look at the documentation of those two commands. I haven't
looked at TAP infrastructure, but you could open a psql session to a
running server and send an arbitrary number of SQL queries through it.

Said that a server starts caching plan only after it sees a certain
number of EXECUTEs. So if you are testing cached plans, that's
something to worry about.

On Tue, Aug 11, 2020 at 8:13 AM Andy Fan <zhihui.fan1213@gmail.com> wrote:
>
> I want to write some test cases with extended query in core test system. basically it looks like
>
> PreparedStatement preparedStatement  = conn.prepareStatement("select * from bigtable");
> preparedStatement.setFetchSize(4);
> ResultSet rs = preparedStatement.executeQuery();
> while(rs.next())
> {
>     System.out.println(rs.getInt(1));
>     // conn.commit();
>     conn.rollback();
> }
>
>
> However I don't find a way to do that after checking the example in src/test/xxx/t/xxx.pl
> where most often used object is PostgresNode, which don't have such abilities.
>
> Can I do that in core system, I tried grep '\->prepare'  and  '\->execute' and get nothing.
> am I miss something?
>
>
> --
> Best Regards
> Andy Fan



-- 
Best Wishes,
Ashutosh Bapat

Andy Fan <zhihui.fan1213@gmail.com> writes:
> I want to write some test cases with extended query in core test system.

Why?  (That is, what is it you need to test exactly?)

psql has no ability to issue extended queries AFAIR, so the normal
regression test scripts can't exercise this.  We haven't built anything
for it in the TAP infrastructure either.  We do have test coverage
via pgbench and ecpg, though I concede that's pretty indirect.

I recall someone (Andres, possibly) speculating about building a tool
specifically to exercise low-level protocol issues, but that hasn't
been done either.

None of these are necessarily germane to any particular test requirement,
which is why I'm wondering.  The JDBC fragment you show seems like it's
something that should be tested by, well, JDBC.  What's interesting about
it for any other client?

            regards, tom lane

Hi,

On 2020-08-11 11:22:49 -0400, Tom Lane wrote:
> I recall someone (Andres, possibly) speculating about building a tool
> specifically to exercise low-level protocol issues, but that hasn't
> been done either.

Yea, I mentioned the possibility, but didn't plan to work on it. I am
not a perl person by any stretch (even though that's where I
started...).  But we can (and do iirc) have tests that just use libpq,
so it should be possible to test things like this at a bit higher cost.

Greetings,

Andres Freund