On 2015-05-10 21:09:14 -0400, Tom Lane wrote: > Andres Freund <and...@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 did check with a quick profile, and the iteration itself is a significant part of the total execution time. > I'd suggest trying something that exercises array_map(), which > it looks like means doing an array coercion. Perhaps like so: > do $$ > declare a int4[]; > x int; > begin > a := array(select generate_series(1,1000)); > for i in 1..100000 loop > x := array_length(a::int8[], 1); > end loop; > end$$; with the loop count set to 10000 instead, I get: before: after: tps = 20.940092 (including connections establishing) after: tps = 20.568730 (including connections establishing) Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
