Re: Manipulating complex types as non-contiguous structures in-memory

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Pavel Stehule <pavel.stehule@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2015-05-11T01:09:14Z
Lists: pgsql-hackers
Andres Freund <andres@anarazel.de> writes:
> I'm not sure what exactly to use as a performance benchmark
> here. For now I chose
> SELECT * FROM (SELECT ARRAY(SELECT generate_series(1, 10000))) d, generate_series(1, 1000) repeat(i);
> that'll hit array_out, which uses iterators.

Hmm, probably those results are swamped by I/O functions though.
I'd suggest trying something that exercises array_map(), which
it looks like means doing an array coercion.  Perhaps like so:

do $$
declare a int4[];
x int;
begin
  a := array(select generate_series(1,1000));
  for i in 1..100000 loop
    x := array_length(a::int8[], 1);
  end loop;
end$$;

Anyway, thanks for poking at it!

			regards, tom lane


Commits

  1. Use fast path in plpgsql's RETURN/RETURN NEXT in more cases.

  2. Add support for multiple kinds of external toast datums.