On Thu, Sep 8, 2016 at 2:13 PM, Peter Geoghegan <p...@heroku.com> wrote: > On Thu, Sep 8, 2016 at 8:53 AM, Claudio Freire <klaussfre...@gmail.com> wrote: >> setup: >> >> create table lotsofitext(i text, j text, w text, z integer, z2 bigint); >> insert into lotsofitext select cast(random() * 1000000000.0 as text) >> || 'blablablawiiiiblabla', cast(random() * 1000000000.0 as text) || >> 'blablablawjjjblabla', cast(random() * 1000000000.0 as text) || >> 'blablabl >> awwwabla', random() * 1000000000.0, random() * 1000000000000.0 from >> generate_series(1, 10000000); >> >> timed: >> >> select count(*) FROM (select * from lotsofitext order by i, j, w, z, z2) t; >> >> Unpatched Time: 100351.251 ms >> Patched Time: 75180.787 ms >> >> That's like a 25% speedup on random input. As we say over here, rather >> badly translated, not a turkey's boogers (meaning "nice!") > > Cool! What work_mem setting were you using here?
The script iterates over a few variations of string patterns (easy comparisons vs hard comparisons), work mem (4MB, 64MB, 256MB, 1GB, 4GB), and table sizes (~350M, ~650M, ~1.5G). That particular case I believe is using work_mem=4MB, easy strings, 1.5GB table. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
