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

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Andres Freund <andres(at)anarazel(dot)de>
Cc: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Manipulating complex types as non-contiguous structures in-memory
Date: 2015-05-11 01:09:14
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Andres Freund <andres(at)anarazel(dot)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;
a := array(select generate_series(1,1000));
for i in 1..100000 loop
x := array_length(a::int8[], 1);
end loop;

Anyway, thanks for poking at it!

regards, tom lane

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