On Wed, Feb 20, 2019 at 2:25 PM Peter Geoghegan wrote:
> I suspect that the reasons why the Lao locale sorts so much slower may
> also have something to do with the intrinsic cost of supporting more
> complicated rules.
I strongly suspect that it has something to do with the issue
described here
On Wed, Feb 20, 2019 at 1:42 PM Bob Jolliffe wrote:
> It seems not to be (completely) particular to the installation.
> Testing on different platforms we found variable speed difference
> between 100x and 1000x slower, but always a considerable order of
> magnitiude. The very slow performance
On Wed, 20 Feb 2019 at 21:35, Merlin Moncure wrote:
>
> On Mon, Feb 18, 2019 at 9:49 AM Bob Jolliffe wrote:
> >
> > Sorry Merlin for not replying earlier. The difference is indeed hard
> > to understand but it is certainly there. We altered the collation to
> > use on the name field in that
On Mon, Feb 18, 2019 at 9:49 AM Bob Jolliffe wrote:
>
> Sorry Merlin for not replying earlier. The difference is indeed hard
> to understand but it is certainly there. We altered the collation to
> use on the name field in that table and the problem has gone. Having
> having solved the
Merlin Moncure wrote:
> yeah, probably. Having said that, I'm really struggling that it can
> take take several minutes to sort such a small number of rows even
> with location issues. I can sort rocks faster than that :-).
>
> Switching between various european collations, I'm seeing subsecond
On Thu, Jan 31, 2019 at 7:30 AM Bob Jolliffe wrote:
>
> Hi Peter
>
> I did check out using ICU and the performance does indeed seem
> comparable with C locale:
>
> EXPLAIN ANALYZE select * from chart order by name COLLATE "lo-x-icu";
> QUERY
Hi Peter
I did check out using ICU and the performance does indeed seem
comparable with C locale:
EXPLAIN ANALYZE select * from chart order by name COLLATE "lo-x-icu";
QUERY PLAN
Hi Tom
After much performance measuring of VPS I believe you are right in
your suspicion about locale.
The database is full of Laos characters (it is a government system in
Laos). When I tested on my VPS (en_US.UTF-8) I get the crazy slow
performance, whereas my laptop postgresql is C.UTF-8.
Bob Jolliffe writes:
> I wonder what can cause such a massive discrepancy in the sort time.
Are you using the same locale (LC_COLLATE) setting on both machines?
Some locales sort way slower than C locale does. That's not enough
to explain a 1000X discrepancy --- I concur with the other opinions
Run https://github.com/n-st/nench and benchmark the underlying vps first.
On Tue 29 Jan, 2019, 11:59 PM Bob Jolliffe The following is output from analyzing a simple query on a table of
> 13436 rows on postgresql 10, ubuntu 18.04.
>
> explain analyze select * from chart order by name;
>
út 29. 1. 2019 v 19:29 odesílatel Bob Jolliffe
napsal:
> The following is output from analyzing a simple query on a table of
> 13436 rows on postgresql 10, ubuntu 18.04.
>
> explain analyze select * from chart order by name;
>QUERY PLAN
>
>
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