pá 17. 2. 2023 v 21:43 odesílatel Jeff Davis <pgsql@j-davis.com> napsal:
On Fri, 2023-02-17 at 18:27 +0100, Pavel Stehule wrote: > Today I tested icu for Czech sorting. It is a little bit slower, but > not too much, but it produces partially different results.
Thank you for trying it.
If it's a significant slowdown, can you please send more information? ICU version, libc version, and testcase?
no - this slowdown is not significant - although 1% can looks too much - but it is just two ms
It looks so libicu has little bit more expensive initialization, but the execution is little bit faster
But when I try to repeat the measurements, the results are very unstable on my desktop :-/
SELECT * FROM obce ORDER BY nazev LIMIT 10 // is faster with glibc little bit
SELECT * FROM obce ORDER BY nazev // is faster with libicu
It is table of municipalities in czech republic (real names) - about 6000 rows
I use fedora 37 - so libicu 71.1, glibc 2.36
Regards
Pavel
> select row_number() over (order by nazev collate "cs-x-icu"), nazev > from obce > except select row_number() over (order by nazev collate "cs_CZ"), > nazev from obce; > > returns a not empty set. So minimally for Czech collate, an index > rebuild is necessary
Yes, that's true of any locale change, provider change, or even provider version change.
