Re: BUG #15285: Query used index over field with ICU collation in some cases wrongly return 0 rows
От | Jehan-Guillaume de Rorthais |
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Тема | Re: BUG #15285: Query used index over field with ICU collation in some cases wrongly return 0 rows |
Дата | |
Msg-id | 20200902145550.6a5014fb@firost обсуждение исходный текст |
Ответ на | Re: BUG #15285: Query used index over field with ICU collation in some cases wrongly return 0 rows (Peter Eisentraut <peter.eisentraut@2ndquadrant.com>) |
Ответы |
Re: BUG #15285: Query used index over field with ICU collation in some cases wrongly return 0 rows
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Список | pgsql-bugs |
On Wed, 2 Sep 2020 14:06:18 +0200 Peter Eisentraut <peter.eisentraut@2ndquadrant.com> wrote: > On 2020-06-10 00:29, Jehan-Guillaume de Rorthais wrote: > > In the meantime, I've been working on various workarounds. The only one I > > found is to use "fr-u-kr-latn-digit-kn" instead of "fr-u-kr-latn-digit". > > Unfortunately, the two collations are not equivalent, but I believe it > > might be useful in many case. > > What precisely is broken in the ICU library? Using ucol_strcoll/ucol_strcollUTF8 with a custom collation sorting digits after latn. > All the examples so far refer to kr-latn-digit. Are all reorderings broken, > or something specifically related to latn and/or digit? I don't know. So far, I only found a couple of reports (mine included) using kr-latn-digit in different languages. And as I wrote, kr-latn-digit-kn doesn't seem affected. So all reorderings might not be broken. But I have no strong facts about this, just tests. > Are any collation customizations other than reorderings affected? I didn't poke around to try some other random customizations. The answer lies somewhere in the ICU codebase. I suppose we'll be able to answer this question as soon as the bug will be explained. However, the bug reported here are all about sorting: wrong result order and/or wrong result because of badly sorted index. Maybe Daniel has some more experience feedback with other customizations as he seems to work extensively with ICU and PostgreSQL? Regards,
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