Обсуждение: Sorting Problem
Currently I'm running PostgreSQL 7.2.3 and having a problem sorting. I've got two colums of data, one Int4 one Varchar. When I sort ASC on the varchar I get some strange results. Here a section of data cut after running a sort. It starts with RM- then does RMT- Then goes back for more RM-. I've checked for spaces or tabs or anything else odd and cant find anything that would effect the sort. 63 RM-791 38 RM-AV2100 9 RM-PP401 10 RM-PP402 8 RM-PP404 3 RMT-D10 4 RMT-D108A 5 RMT-D109A 6 RMT-D116A 34 RMT-V402 40 RM-V10 41 RM-V11 45 RM-V12 Here's the sort string I'm using: SELECT "remote_id", "remote_model" FROM "remote" ORDER BY "remote_model" ASC; Any idea or suggestions why it would do this ? _________________________________________________________________ MSN 8 with e-mail virus protection service: 2 months FREE* http://join.msn.com/?page=features/virus
"Tim Edwards" <mor4321@hotmail.com> writes:
> When I sort ASC on the varchar I get some strange results. Here a section of
> data cut after running a sort. It starts with RM- then does RMT- Then goes
> back for more RM-.
Sounds like you're in en_US locale, or at least something other than C
locale.
Unfortunately this can only be fixed by re-initdb'ing :-(
regards, tom lane
Do you mean that soring doesn't work for en_US locale ??? And, does encoding affect sorting at all ?? thanks, kathy Tom Lane wrote: > "Tim Edwards" <mor4321@hotmail.com> writes: > >>When I sort ASC on the varchar I get some strange results. Here a section of >>data cut after running a sort. It starts with RM- then does RMT- Then goes >>back for more RM-. > > > Sounds like you're in en_US locale, or at least something other than C > locale. > > Unfortunately this can only be fixed by re-initdb'ing :-( > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) --
To help my understanding of this type of thing, when he reinits the database, can he get the PG backend to be running witha different LOCALE than the machine's? Tom Lane wrote: > "Tim Edwards" <mor4321@hotmail.com> writes: > >>When I sort ASC on the varchar I get some strange results. Here a section of >>data cut after running a sort. It starts with RM- then does RMT- Then goes >>back for more RM-. > > > Sounds like you're in en_US locale, or at least something other than C > locale. > > Unfortunately this can only be fixed by re-initdb'ing :-( > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) >
en_US locale skips? punctuation from sorting index,
so in your case
RM-791
RM-AV2100
RM-PP401
RM-PP402
RM-PP404
RM-V10
RM-V11
RM-V12
RMT-D10
RMT-D108A
RMT-D109A
RMT-D116A
RMT-V402
==>
RM791
RMAV2100
RMPP401
RMPP402
RMPP404
RMV10
RMV11
RMV12
RMTD10
RMTD108A
RMTD109A
RMTD116A
RMTV402
-----Original Message-----
From: Kathy zhu [mailto:Kathy.zhu@Sun.COM]
Sent: Tuesday, August 12, 2003 3:30 PM
To: Tom Lane
Cc: Tim Edwards; pgsql-general@postgresql.org
Subject: Re: [GENERAL] Sorting Problem
Do you mean that soring doesn't work for en_US locale ???
And, does encoding affect sorting at all ??
thanks,
kathy
Tom Lane wrote:
> "Tim Edwards" <mor4321@hotmail.com> writes:
>
>>When I sort ASC on the varchar I get some strange results. Here a
section of
>>data cut after running a sort. It starts with RM- then does RMT- Then
goes
>>back for more RM-.
>
>
> Sounds like you're in en_US locale, or at least something other than C
> locale.
>
> Unfortunately this can only be fixed by re-initdb'ing :-(
>
> regards, tom lane
>
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Dennis Gearon <gearond@cvc.net> writes:
> To help my understanding of this type of thing, when he reinits the database, can he get the PG backend to be running
witha different LOCALE than the machine's?
Yeah, he needs to set LANG and/or LC_ALL to be 'C' instead of whatever
it's defaulting to on his machine. Then run initdb with that
environment, and he's set.
regards, tom lane
Kathy zhu <Kathy.zhu@Sun.COM> writes:
> Do you mean that soring doesn't work for en_US locale ???
Oh it works all right, it just doesn't agree with Tim's idea of what
sorted order is ;-)
regards, tom lane
If it skips "-", then RMT-* should come before RM-V*, but they don't, why ?? Maksim Likharev wrote: > en_US locale skips? punctuation from sorting index, > so in your case > > RM-791 > RM-AV2100 > RM-PP401 > RM-PP402 > RM-PP404 > RM-V10 > RM-V11 > RM-V12 > RMT-D10 > RMT-D108A > RMT-D109A > RMT-D116A > RMT-V402 > > ==> > > RM791 > RMAV2100 > RMPP401 > RMPP402 > RMPP404 > RMV10 > RMV11 > RMV12 > RMTD10 > RMTD108A > RMTD109A > RMTD116A > RMTV402 > > -----Original Message----- > From: Kathy zhu [mailto:Kathy.zhu@Sun.COM] > Sent: Tuesday, August 12, 2003 3:30 PM > To: Tom Lane > Cc: Tim Edwards; pgsql-general@postgresql.org > Subject: Re: [GENERAL] Sorting Problem > > > Do you mean that soring doesn't work for en_US locale ??? > And, does encoding affect sorting at all ?? > > thanks, > kathy > > Tom Lane wrote: > >>"Tim Edwards" <mor4321@hotmail.com> writes: >> >> >>>When I sort ASC on the varchar I get some strange results. Here a >> > section of > >>>data cut after running a sort. It starts with RM- then does RMT- Then >> > goes > >>>back for more RM-. >> >> >>Sounds like you're in en_US locale, or at least something other than C >>locale. >> >>Unfortunately this can only be fixed by re-initdb'ing :-( >> >> regards, tom lane >> >>---------------------------(end of > > broadcast)--------------------------- > >>TIP 2: you can get off all lists at once with the unregister command >> (send "unregister YourEmailAddressHere" to > > majordomo@postgresql.org) > > --
You mean in his own local environment? So all his programs, console operations, etc, will have the new encoding? Or 'LANG/LC_ALL'for Posgres specifically? Tom Lane wrote: > Dennis Gearon <gearond@cvc.net> writes: > >>To help my understanding of this type of thing, when he reinits the database, can he get the PG backend to be running witha different LOCALE than the machine's? > > > Yeah, he needs to set LANG and/or LC_ALL to be 'C' instead of whatever > it's defaulting to on his machine. Then run initdb with that > environment, and he's set. > > regards, tom lane >
It does if you look at the original email. Maksim must've just transposed a couple letters when he was writing his demo. Jeff Kathy zhu wrote: > If it skips "-", then RMT-* should come before RM-V*, but they don't, > why ?? > > > Maksim Likharev wrote: > >> en_US locale skips? punctuation from sorting index, >> so in your case >> >> RM-791 >> RM-AV2100 >> RM-PP401 >> RM-PP402 >> RM-PP404 >> RM-V10 >> RM-V11 >> RM-V12 >> RMT-D10 >> RMT-D108A >> RMT-D109A >> RMT-D116A >> RMT-V402 >> >> ==> >> >> RM791 >> RMAV2100 >> RMPP401 >> RMPP402 >> RMPP404 >> RMV10 >> RMV11 >> RMV12 >> RMTD10 >> RMTD108A >> RMTD109A >> RMTD116A >> RMTV402 >> >> -----Original Message----- >> From: Kathy zhu [mailto:Kathy.zhu@Sun.COM] >> Sent: Tuesday, August 12, 2003 3:30 PM >> To: Tom Lane >> Cc: Tim Edwards; pgsql-general@postgresql.org >> Subject: Re: [GENERAL] Sorting Problem >> >> >> Do you mean that soring doesn't work for en_US locale ??? >> And, does encoding affect sorting at all ?? >> >> thanks, >> kathy >> >> Tom Lane wrote: >> >>> "Tim Edwards" <mor4321@hotmail.com> writes: >>> >>> >>>> When I sort ASC on the varchar I get some strange results. Here a >>> >>> >> section of >> >>>> data cut after running a sort. It starts with RM- then does RMT- Then >>> >>> >> goes >> >>>> back for more RM-. >>> >>> >>> >>> Sounds like you're in en_US locale, or at least something other than C >>> locale. >>> >>> Unfortunately this can only be fixed by re-initdb'ing :-( >>> >>> regards, tom lane >>> >>> ---------------------------(end of >> >> >> broadcast)--------------------------- >> >>> TIP 2: you can get off all lists at once with the unregister command >>> (send "unregister YourEmailAddressHere" to >> >> >> majordomo@postgresql.org) >> >>
Danke, Spacibo, gracias, thanks. Tom Lane wrote: > Dennis Gearon <gearond@cvc.net> writes: > >>You mean in his own local environment? So all his programs, console operations, etc, will have the new encoding? Or 'LANG/LC_ALL'for Posgres specifically? > > > I mean he needs to run initdb with C as the selected locale. It has > nothing to do with what environment his other programs run in. > > regards, tom lane >
Dennis Gearon <gearond@cvc.net> writes:
> You mean in his own local environment? So all his programs, console operations, etc, will have the new encoding? Or
'LANG/LC_ALL'for Posgres specifically?
I mean he needs to run initdb with C as the selected locale. It has
nothing to do with what environment his other programs run in.
regards, tom lane
and they come: sorted asc: RM-791 RM-AV2100 RM-PP401 RM-PP402 RM-PP404 RMT-D10 RMT-D108A RMT-D109A RMT-D116A RMT-V402 RM-V10 RM-V11 RM-V12 sorted asc: RM791 RMAV2100 RMPP401 RMPP402 RMPP404 RMTD10 RMTD108A RMTD109A RMTD116A RMTV402 RMV10 RMV11 RMV12 I think I copied and pasted wrogn, sorry. -----Original Message----- From: Kathy zhu [mailto:Kathy.zhu@Sun.COM] Sent: Tuesday, August 12, 2003 4:08 PM To: Maksim Likharev Cc: pgsql-general@postgresql.org Subject: Re: [GENERAL] Sorting Problem If it skips "-", then RMT-* should come before RM-V*, but they don't, why ?? Maksim Likharev wrote: > en_US locale skips? punctuation from sorting index, > so in your case > > RM-791 > RM-AV2100 > RM-PP401 > RM-PP402 > RM-PP404 > RM-V10 > RM-V11 > RM-V12 > RMT-D10 > RMT-D108A > RMT-D109A > RMT-D116A > RMT-V402 > > ==> > > RM791 > RMAV2100 > RMPP401 > RMPP402 > RMPP404 > RMV10 > RMV11 > RMV12 > RMTD10 > RMTD108A > RMTD109A > RMTD116A > RMTV402 > > -----Original Message----- > From: Kathy zhu [mailto:Kathy.zhu@Sun.COM] > Sent: Tuesday, August 12, 2003 3:30 PM > To: Tom Lane > Cc: Tim Edwards; pgsql-general@postgresql.org > Subject: Re: [GENERAL] Sorting Problem > > > Do you mean that soring doesn't work for en_US locale ??? > And, does encoding affect sorting at all ?? > > thanks, > kathy > > Tom Lane wrote: > >>"Tim Edwards" <mor4321@hotmail.com> writes: >> >> >>>When I sort ASC on the varchar I get some strange results. Here a >> > section of > >>>data cut after running a sort. It starts with RM- then does RMT- Then >> > goes > >>>back for more RM-. >> >> >>Sounds like you're in en_US locale, or at least something other than C >>locale. >> >>Unfortunately this can only be fixed by re-initdb'ing :-( >> >> regards, tom lane >> >>---------------------------(end of > > broadcast)--------------------------- > >>TIP 2: you can get off all lists at once with the unregister command >> (send "unregister YourEmailAddressHere" to > > majordomo@postgresql.org) > > --
This brings up another question: Say initdb with en_US locale, and we have localized strings for different languages store in the db. If we have a client in Germany, and want to see the text sorted in german. I mean that we want do db soring for german strings and display the result in the browser. How are we going to handle that ?? thanks, kathy Dennis Gearon wrote: > Danke, Spacibo, gracias, thanks. > > Tom Lane wrote: > >> Dennis Gearon <gearond@cvc.net> writes: >> >>> You mean in his own local environment? So all his programs, console >>> operations, etc, will have the new encoding? Or 'LANG/LC_ALL' for >>> Posgres specifically? >> >> >> >> I mean he needs to run initdb with C as the selected locale. It has >> nothing to do with what environment his other programs run in. >> >> regards, tom lane >> > > > ---------------------------(end of broadcast)--------------------------- > TIP 7: don't forget to increase your free space map settings --
If you are talking about everything that lies under so called LATIN-1 (
ISO-8859-1 )
en_US encapsulates ( at least suppose to ) all those sorting rules,
do not remember about accents tho.
-----Original Message-----
From: Kathy zhu [mailto:Kathy.zhu@Sun.COM]
Sent: Tuesday, August 12, 2003 4:43 PM
To: gearond@cvc.net
Cc: Tom Lane; Tim Edwards; pgsql-general@postgresql.org
Subject: Re: [GENERAL] Sorting Problem
This brings up another question:
Say initdb with en_US locale, and we have localized strings for
different
languages store in the db.
If we have a client in Germany, and want to see the text sorted in
german. I
mean that we want do db soring for german strings and display the result
in the
browser. How are we going to handle that ??
thanks,
kathy
Dennis Gearon wrote:
> Danke, Spacibo, gracias, thanks.
>
> Tom Lane wrote:
>
>> Dennis Gearon <gearond@cvc.net> writes:
>>
>>> You mean in his own local environment? So all his programs, console
>>> operations, etc, will have the new encoding? Or 'LANG/LC_ALL' for
>>> Posgres specifically?
>>
>>
>>
>> I mean he needs to run initdb with C as the selected locale. It has
>> nothing to do with what environment his other programs run in.
>>
>> regards, tom lane
>>
>
>
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http://archives.postgresql.org
Does including sorting rules for asian chars too ?? Do you know where I can find docuemt on this subject ?? thanks, kathy Maksim Likharev wrote: >If you are talking about everything that lies under so called LATIN-1 ( >ISO-8859-1 ) >en_US encapsulates ( at least suppose to ) all those sorting rules, >do not remember about accents tho. > > >-----Original Message----- >From: Kathy zhu [mailto:Kathy.zhu@Sun.COM] >Sent: Tuesday, August 12, 2003 4:43 PM >To: gearond@cvc.net >Cc: Tom Lane; Tim Edwards; pgsql-general@postgresql.org >Subject: Re: [GENERAL] Sorting Problem > > >This brings up another question: > >Say initdb with en_US locale, and we have localized strings for >different >languages store in the db. > >If we have a client in Germany, and want to see the text sorted in >german. I >mean that we want do db soring for german strings and display the result >in the >browser. How are we going to handle that ?? > >thanks, >kathy > > > > >Dennis Gearon wrote: > > >>Danke, Spacibo, gracias, thanks. >> >>Tom Lane wrote: >> >> >> >>>Dennis Gearon <gearond@cvc.net> writes: >>> >>> >>> >>>>You mean in his own local environment? So all his programs, console >>>>operations, etc, will have the new encoding? Or 'LANG/LC_ALL' for >>>>Posgres specifically? >>>> >>>> >>> >>>I mean he needs to run initdb with C as the selected locale. It has >>>nothing to do with what environment his other programs run in. >>> >>> regards, tom lane >>> >>> >>> >>---------------------------(end of >> >> >broadcast)--------------------------- > > >>TIP 7: don't forget to increase your free space map settings >> >> > > > >
On Tue, 12 Aug 2003, Maksim Likharev wrote: > If you are talking about everything that lies under so called LATIN-1 ( > ISO-8859-1 ) en_US encapsulates ( at least suppose to ) all those > sorting rules, do not remember about accents tho. It does not work like that. Different countries in europe that all use latin1 use different sort order for the same characters. There is no way to have one set of rules work for all. If we take swedish for example, then v and w is treatead as the same letter when sorting. So in a dictionary all words beginning with v or w is mixed together. In the future we need indexes that depend on the locale (and a lot of other changes). -- /Dennis
I was afraid of something like that. I found a sort term fix by using the following: select remote_model, translate(remote_model, '-', 'a') from remote order by translate(remote_model, '-', 'a') asc But it's an ugly answer to this, but it works for now. Guess I'm going to be readin up on Locales _________________________________________________________________ Help STOP SPAM with the new MSN 8 and get 2 months FREE* http://join.msn.com/?page=features/junkmail
Dennis Björklund wrote: > In the future we need indexes that depend on the locale (and a lot of other changes). > I agree. I've been looking at the web on this subject a lot lately. I am **NOT** a microslop fan, but SQL-SERVER even letsa user define a language(maybe encoding) down to the column level! I've been reading on GNU-C and on languages, encoding, and localization. http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper-1.html http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2366,1222,00.html There are three basic approaches to doing different langauges in computerized text: A/ various adaptations of the 8 bit character set, I.E. the ISO-8859-x series. One byte per character. Easy storing, small size for a string. Easy storing, if english characters, 100% efficient use of storage space. Easy processing between applications, works well in the stream model of *nix Easy processing in applications, a byte is a character. Easy string handling, NOY NULL bytes in a string, except end of string. NOT easy to know encoding from inherently in the document. This is not the way of the future. B/ wide characters UTF16, UTF32, SHIFT-JIS-16, others each character the same width, 2 or 4 bytes (2 bytes handles 99% of all languages) Not so easy storing, if english characters, 50% to 75% loss of storage space. Difficult processing between applications, does NOT work well in the stream model of *nix Easy processing in applications, a set width of bits/bytes is a character. Difficult string handling, MANY NULL bytes in a string, especially if in English. Moderately easy to tell encoding/language in the document. ********This should be how Postgress stores data internally.******** C/ Multibyte characters UTF8 variable width for different characters 1-5 Not so easy storing, if non english characters, 50% to 80% loss of storage space, (in reality, most common western languages hover aournd 5-20% loss of storage space most common non western languages hover aournd 40-60%% loss of storage space) Easy processing between applications, works well in the stream model of *nix Difficult processing in applications, a variable number of bytes is a character. Easy string string handling, ONE NULL byte in a string. Moderately easy to tell encoding/language in the document. ********This is how Postgress should default to sending data OUT of the application, i.e. to the display or the web, or other system applications******** >
On Wed, 13 Aug 2003, Dennis Gearon wrote: > Dennis Bj�rklund wrote: > > > In the future we need indexes that depend on the locale (and a lot of other changes). > > > > I agree. I've been looking at the web on this subject a lot lately. I > am **NOT** a microslop fan, but SQL-SERVER even lets a user define a > language(maybe encoding) down to the column level! > > I've been reading on GNU-C and on languages, encoding, and localization. > > http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper-1.html > http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2366,1222,00.html > > > There are three basic approaches to doing different langauges in computerized text: > > A/ various adaptations of the 8 bit character set, I.E. the ISO-8859-x series. > B/ wide characters > ********This should be how Postgress stores data internally.******** > C/ Multibyte characters > ********This is how Postgress should default to sending data OUT of the application, > i.e. to the display or the web, or other system applications******** SQL has a system for defining character set specifications, collations and such (per column/literal in some cases). We should probably look at it before making decisions on how to do things.
Got a link to that section of the standard, or better yet, to a 'interpreted' version of the standard? :-) Stephan Szabo wrote: > On Wed, 13 Aug 2003, Dennis Gearon wrote: > > >>Dennis Bj?rklund wrote: >> >> >>>In the future we need indexes that depend on the locale (and a lot of other changes). >>> >> >>I agree. I've been looking at the web on this subject a lot lately. I >>am **NOT** a microslop fan, but SQL-SERVER even lets a user define a >>language(maybe encoding) down to the column level! >> >>I've been reading on GNU-C and on languages, encoding, and localization. >> >>http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper-1.html >>http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2366,1222,00.html >> >> >>There are three basic approaches to doing different langauges in computerized text: >> >> A/ various adaptations of the 8 bit character set, I.E. the ISO-8859-x series. >> B/ wide characters >> ********This should be how Postgress stores data internally.******** >> C/ Multibyte characters >> ********This is how Postgress should default to sending data OUT of the application, >> i.e. to the display or the web, or other system applications******** > > > SQL has a system for defining character set specifications, collations and > such (per column/literal in some cases). We should probably look at it > before making decisions on how to do things. > > > ---------------------------(end of broadcast)--------------------------- > TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org >
Not only SQL Server has all those possible cases for collate, but it does work very well. Assigning collate/encoding per column probably too much ( I never used it in my life ) but assigning collate/encoding per table very much helpful. Case insensitive collation another very useful thing, which is on by default ( in SQL Server ) and I really missing it in postgres, although I might probably initdb with some wacky case insensitive collate but that's more theoretical then practical. And of cause on top of that, ability to store UTF-16 data in a column ( build in data type ) independent of db collate would be priceless which SQL Server allow to do. Not much of dithyrambs for SQL Server but rather reality. Thanks. -----Original Message----- From: Stephan Szabo [mailto:sszabo@megazone.bigpanda.com] Sent: Wednesday, August 13, 2003 9:32 AM To: Dennis Gearon Cc: Dennis Björklund; Maksim Likharev; pgsql-general@postgresql.org Subject: Re: [GENERAL] Sorting Problem On Wed, 13 Aug 2003, Dennis Gearon wrote: > Dennis Björklund wrote: > > > In the future we need indexes that depend on the locale (and a lot of other changes). > > > > I agree. I've been looking at the web on this subject a lot lately. I > am **NOT** a microslop fan, but SQL-SERVER even lets a user define a > language(maybe encoding) down to the column level! > > I've been reading on GNU-C and on languages, encoding, and localization. > > http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper- 1.html > http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2 366,1222,00.html > > > There are three basic approaches to doing different langauges in computerized text: > > A/ various adaptations of the 8 bit character set, I.E. the ISO-8859-x series. > B/ wide characters > ********This should be how Postgress stores data internally.******** > C/ Multibyte characters > ********This is how Postgress should default to sending data OUT of the application, > i.e. to the display or the web, or other system applications******** SQL has a system for defining character set specifications, collations and such (per column/literal in some cases). We should probably look at it before making decisions on how to do things.
On Wed, 13 Aug 2003, Dennis Gearon wrote:
> Got a link to that section of the standard, or better yet, to a
> 'interpreted' version of the standard? :-)
The standard draft yes, an interpreted version, unfortunately not (unless
Date's book covers it and I can find where my copy is.
Here are some of the highlights
----
k) form-of-use: A convention (or encoding) for representing
characters (in character strings). Some forms-of-use are
fixed-length codings and others are variable-length codings.
l) form-of-use conversion: A method of converting character
strings from one form-of-use to another form-of-use.
----
A character set is described by a character set descriptor. A
character set descriptor includes:
- the name of the character set or character repertoire,
- if the character set is a character repertoire, then the name of
the form-of-use,
- an indication of what characters are in the character set, and
- the name of the default collation of the character set.
For every character set, there is at least one collation. A
collation is described by a collation descriptor. A collation descriptor
includes:
- the name of the collation,
- the name of the character set on which the collation operates,
- whether the collation has the NO PAD or the PAD SPACE attribute,
and
- an indication of how the collation is performed.
---
The character data types and literals can include a character set
definition. Character type columns can include a collation. There's a
COLLATE <blah> clause that looks like it can be used in expressions as
well.
If we really want to do it, we won't have to do the grunt work ourselves, just the tie-in, and Postgres specific
implementation:
http://www.unicode.org/reports/tr10/
Stephan Szabo wrote:
> On Wed, 13 Aug 2003, Dennis Gearon wrote:
>
>
>>Got a link to that section of the standard, or better yet, to a
>>'interpreted' version of the standard? :-)
>
>
> The standard draft yes, an interpreted version, unfortunately not (unless
> Date's book covers it and I can find where my copy is.
>
> Here are some of the highlights
>
> ----
> k) form-of-use: A convention (or encoding) for representing
> characters (in character strings). Some forms-of-use are
> fixed-length codings and others are variable-length codings.
>
> l) form-of-use conversion: A method of converting character
> strings from one form-of-use to another form-of-use.
>
> ----
> A character set is described by a character set descriptor. A
> character set descriptor includes:
>
> - the name of the character set or character repertoire,
>
> - if the character set is a character repertoire, then the name of
> the form-of-use,
>
> - an indication of what characters are in the character set, and
>
> - the name of the default collation of the character set.
>
> For every character set, there is at least one collation. A
> collation is described by a collation descriptor. A collation descriptor
> includes:
>
> - the name of the collation,
>
> - the name of the character set on which the collation operates,
>
> - whether the collation has the NO PAD or the PAD SPACE attribute,
> and
>
> - an indication of how the collation is performed.
>
> ---
>
> The character data types and literals can include a character set
> definition. Character type columns can include a collation. There's a
> COLLATE <blah> clause that looks like it can be used in expressions as
> well.
>
>
Dennis Gearon wrote: > Got a link to that section of the standard, or better yet, to a > 'interpreted' version of the standard? :-) > > Stephan Szabo wrote: > >> On Wed, 13 Aug 2003, Dennis Gearon wrote: >> >> >>> Dennis Bj?rklund wrote: >>> >>> >>>> In the future we need indexes that depend on the locale (and a lot >>>> of other changes). >>>> >>> >>> I agree. I've been looking at the web on this subject a lot lately. I >>> am **NOT** a microslop fan, but SQL-SERVER even lets a user define a >>> language(maybe encoding) down to the column level! >>> >>> I've been reading on GNU-C and on languages, encoding, and >>> localization. >>> >>> http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper-1.html >>> >>> http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2366,1222,00.html >>> >>> >>> >>> There are three basic approaches to doing different langauges in >>> computerized text: >>> >>> A/ various adaptations of the 8 bit character set, I.E. the >>> ISO-8859-x series. >>> B/ wide characters >>> ********This should be how Postgress stores data internally.******** >>> C/ Multibyte characters >>> ********This is how Postgress should default to sending data OUT >>> of the application, >>> i.e. to the display or the web, or other system >>> applications******** >> >> >> >> SQL has a system for defining character set specifications, >> collations and >> such (per column/literal in some cases). We should probably look at it >> before making decisions on how to do things. > I thought UNIX (SCOTM) systems also had a way of being able to define collation order. see: ftp://dkuug.dk/i18n/WG15-collection/locales for a collection of all ISO standardized locales (the WG15 ISO work group's stuff). Do a "man localedef" on most Linuxen or UNIXen. As for wide characters vs multibyte, there is no clear winner. The right answer DEPENDS on the situation. Wide characters on some platforms are 16 bit which means that when you do Unicode you'll still have problems with surrogate pairs (meaning that it's still multi (wide) char) so you still have all the problems of multi-byte encodings. You could decide to process everything in a PG specific 4 byte wide char and do all text in Unicode but the overhead in processing 4 times the data is quite significant. The other option is to store all data in utf-8 and have all text code become utf-8 aware. I have found in practice that the utf-8 option is significantly easier to implement, 100% Unicode compliant and the best performer (because of reduced memory requirements). The Posix API's for locales are not very good for modern day programs, I'm not sure where the "mbr*" and the "wcr*" apis are in the standardization process but if these are not well supported, you're on your own and will need to implement similar functionality from scratch and for that matter, the collation functions all operate on a "current" locate which is really difficult to work with on multi-locale applications.
total agreement, ?????? (Maksim). Maksim Likharev wrote: > Not only SQL Server has all those possible cases for collate, > but it does work very well. > > Assigning collate/encoding per column probably too much ( I never used > it in my life ) > but assigning collate/encoding per table very much helpful. > > Case insensitive collation another very useful thing, which is on by > default ( in SQL Server ) > and I really missing it in postgres, although I might probably initdb > with some wacky > case insensitive collate but that's more theoretical then practical. > > And of cause on top of that, ability to store UTF-16 data in a column ( > build in data type ) > independent of db collate would be priceless which SQL Server allow to > do. > Not much of dithyrambs for SQL Server but rather reality. > > Thanks. > > -----Original Message----- > From: Stephan Szabo [mailto:sszabo@megazone.bigpanda.com] > Sent: Wednesday, August 13, 2003 9:32 AM > To: Dennis Gearon > Cc: Dennis Björklund; Maksim Likharev; pgsql-general@postgresql.org > Subject: Re: [GENERAL] Sorting Problem > > > > On Wed, 13 Aug 2003, Dennis Gearon wrote: > > >>Dennis Björklund wrote: >> >> >>>In the future we need indexes that depend on the locale (and a lot > > of other changes). > >>I agree. I've been looking at the web on this subject a lot lately. I >>am **NOT** a microslop fan, but SQL-SERVER even lets a user define a >>language(maybe encoding) down to the column level! >> >>I've been reading on GNU-C and on languages, encoding, and > > localization. > >> > http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper- > 1.html > > http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2 > 366,1222,00.html > >> >>There are three basic approaches to doing different langauges in > > computerized text: > >> A/ various adaptations of the 8 bit character set, I.E. the > > ISO-8859-x series. > >> B/ wide characters >> ********This should be how Postgress stores data > > internally.******** > >> C/ Multibyte characters >> ********This is how Postgress should default to sending data OUT > > of the application, > >> i.e. to the display or the web, or other system > > applications******** > > SQL has a system for defining character set specifications, collations > and > such (per column/literal in some cases). We should probably look at it > before making decisions on how to do things. > > > ---------------------------(end of broadcast)--------------------------- > TIP 9: the planner will ignore your desire to choose an index scan if your > joining column's datatypes do not match >
I agree with all of that except for one caveat:
all my reading, and just general off the cuff thinking, says that processing variable width characters
SIGNIFICANTLYslows an application. It seems better to PROCESS fixed width characters (1,2,4 byte), and TRANSMIT
variablewidth characters (avoiding the null problem.)
Gianni Mariani wrote:
> Dennis Gearon wrote:
>
>> Got a link to that section of the standard, or better yet, to a
>> 'interpreted' version of the standard? :-)
>>
>> Stephan Szabo wrote:
>>
>>> On Wed, 13 Aug 2003, Dennis Gearon wrote:
>>>
>>>
>>>> Dennis Bj?rklund wrote:
>>>>
>>>>
>>>>> In the future we need indexes that depend on the locale (and a lot
>>>>> of other changes).
>>>>>
>>>>
>>>> I agree. I've been looking at the web on this subject a lot lately. I
>>>> am **NOT** a microslop fan, but SQL-SERVER even lets a user define a
>>>> language(maybe encoding) down to the column level!
>>>>
>>>> I've been reading on GNU-C and on languages, encoding, and
>>>> localization.
>>>>
>>>> http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper-1.html
>>>>
>>>> http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2366,1222,00.html
>>>>
>>>>
>>>>
>>>> There are three basic approaches to doing different langauges in
>>>> computerized text:
>>>>
>>>> A/ various adaptations of the 8 bit character set, I.E. the
>>>> ISO-8859-x series.
>>>> B/ wide characters
>>>> ********This should be how Postgress stores data internally.********
>>>> C/ Multibyte characters
>>>> ********This is how Postgress should default to sending data OUT
>>>> of the application,
>>>> i.e. to the display or the web, or other system
>>>> applications********
>>>
>>>
>>>
>>>
>>> SQL has a system for defining character set specifications,
>>> collations and
>>> such (per column/literal in some cases). We should probably look at it
>>> before making decisions on how to do things.
>>
>>
>
> I thought UNIX (SCOTM) systems also had a way of being able to define
> collation order.
>
> see:
> ftp://dkuug.dk/i18n/WG15-collection/locales
>
> for a collection of all ISO standardized locales (the WG15 ISO work
> group's stuff).
>
> Do a "man localedef" on most Linuxen or UNIXen.
>
> As for wide characters vs multibyte, there is no clear winner. The
> right answer DEPENDS on the situation.
>
> Wide characters on some platforms are 16 bit which means that when you
> do Unicode you'll still have problems with surrogate pairs (meaning that
> it's still multi (wide) char) so you still have all the problems of
> multi-byte encodings.
>
> You could decide to process everything in a PG specific 4 byte wide char
> and do all text in Unicode but the overhead in processing 4 times the
> data is quite significant. The other option is to store all data in
> utf-8 and have all text code become utf-8 aware.
>
> I have found in practice that the utf-8 option is significantly easier
> to implement, 100% Unicode compliant and the best performer (because of
> reduced memory requirements).
> The Posix API's for locales are not very good for modern day programs,
> I'm not sure where the "mbr*" and the "wcr*" apis are in the
> standardization process but if these are not well supported, you're on
> your own and will need to implement similar functionality from scratch
> and for that matter, the collation functions all operate on a "current"
> locate which is really difficult to work with on multi-locale applications.
>
>
>
>
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 8: explain analyze is your friend
>
I think the question is how often are you passing data around/storing it _in_ your application and how often are you processing it. --------------------------------------------------------------------------- Dennis Gearon wrote: > I agree with all of that except for one caveat: > > all my reading, and just general off the cuff thinking, says that processing variable width characters SIGNIFICANTLYslows an application. It seems better to PROCESS fixed width characters (1,2,4 byte), and TRANSMIT variablewidth characters (avoiding the null problem.) > > Gianni Mariani wrote: > > > Dennis Gearon wrote: > > > >> Got a link to that section of the standard, or better yet, to a > >> 'interpreted' version of the standard? :-) > >> > >> Stephan Szabo wrote: > >> > >>> On Wed, 13 Aug 2003, Dennis Gearon wrote: > >>> > >>> > >>>> Dennis Bj?rklund wrote: > >>>> > >>>> > >>>>> In the future we need indexes that depend on the locale (and a lot > >>>>> of other changes). > >>>>> > >>>> > >>>> I agree. I've been looking at the web on this subject a lot lately. I > >>>> am **NOT** a microslop fan, but SQL-SERVER even lets a user define a > >>>> language(maybe encoding) down to the column level! > >>>> > >>>> I've been reading on GNU-C and on languages, encoding, and > >>>> localization. > >>>> > >>>> http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper-1.html > >>>> > >>>> http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2366,1222,00.html > >>>> > >>>> > >>>> > >>>> There are three basic approaches to doing different langauges in > >>>> computerized text: > >>>> > >>>> A/ various adaptations of the 8 bit character set, I.E. the > >>>> ISO-8859-x series. > >>>> B/ wide characters > >>>> ********This should be how Postgress stores data internally.******** > >>>> C/ Multibyte characters > >>>> ********This is how Postgress should default to sending data OUT > >>>> of the application, > >>>> i.e. to the display or the web, or other system > >>>> applications******** > >>> > >>> > >>> > >>> > >>> SQL has a system for defining character set specifications, > >>> collations and > >>> such (per column/literal in some cases). We should probably look at it > >>> before making decisions on how to do things. > >> > >> > > > > I thought UNIX (SCOTM) systems also had a way of being able to define > > collation order. > > > > see: > > ftp://dkuug.dk/i18n/WG15-collection/locales > > > > for a collection of all ISO standardized locales (the WG15 ISO work > > group's stuff). > > > > Do a "man localedef" on most Linuxen or UNIXen. > > > > As for wide characters vs multibyte, there is no clear winner. The > > right answer DEPENDS on the situation. > > > > Wide characters on some platforms are 16 bit which means that when you > > do Unicode you'll still have problems with surrogate pairs (meaning that > > it's still multi (wide) char) so you still have all the problems of > > multi-byte encodings. > > > > You could decide to process everything in a PG specific 4 byte wide char > > and do all text in Unicode but the overhead in processing 4 times the > > data is quite significant. The other option is to store all data in > > utf-8 and have all text code become utf-8 aware. > > > > I have found in practice that the utf-8 option is significantly easier > > to implement, 100% Unicode compliant and the best performer (because of > > reduced memory requirements). > > The Posix API's for locales are not very good for modern day programs, > > I'm not sure where the "mbr*" and the "wcr*" apis are in the > > standardization process but if these are not well supported, you're on > > your own and will need to implement similar functionality from scratch > > and for that matter, the collation functions all operate on a "current" > > locate which is really difficult to work with on multi-locale applications. > > > > > > > > > > > > > > > > ---------------------------(end of broadcast)--------------------------- > > TIP 8: explain analyze is your friend > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 7: don't forget to increase your free space map settings > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073
Agreement about what, necessity of collate per table and Unicode build in data type, hail yeah... but that's really change nothing unless I get big shovel and start "digging on" by my own producing in reasonable period of time something... and even for that, nobody guarantee that my exercise will be even considered by core team... So guess not really an answer -----Original Message----- From: Dennis Gearon [mailto:gearond@cvc.net] Sent: Wednesday, August 13, 2003 11:00 AM To: Maksim Likharev Cc: pgsql-general@postgresql.org Subject: Re: [GENERAL] Sorting Problem total agreement, ?????? (Maksim). Maksim Likharev wrote: > Not only SQL Server has all those possible cases for collate, > but it does work very well. > > Assigning collate/encoding per column probably too much ( I never used > it in my life ) > but assigning collate/encoding per table very much helpful. > > Case insensitive collation another very useful thing, which is on by > default ( in SQL Server ) > and I really missing it in postgres, although I might probably initdb > with some wacky > case insensitive collate but that's more theoretical then practical. > > And of cause on top of that, ability to store UTF-16 data in a column ( > build in data type ) > independent of db collate would be priceless which SQL Server allow to > do. > Not much of dithyrambs for SQL Server but rather reality. > > Thanks. > > -----Original Message----- > From: Stephan Szabo [mailto:sszabo@megazone.bigpanda.com] > Sent: Wednesday, August 13, 2003 9:32 AM > To: Dennis Gearon > Cc: Dennis Björklund; Maksim Likharev; pgsql-general@postgresql.org > Subject: Re: [GENERAL] Sorting Problem > > > > On Wed, 13 Aug 2003, Dennis Gearon wrote: > > >>Dennis Björklund wrote: >> >> >>>In the future we need indexes that depend on the locale (and a lot > > of other changes). > >>I agree. I've been looking at the web on this subject a lot lately. I >>am **NOT** a microslop fan, but SQL-SERVER even lets a user define a >>language(maybe encoding) down to the column level! >> >>I've been reading on GNU-C and on languages, encoding, and > > localization. > >> > http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper- > 1.html > > http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2 > 366,1222,00.html > >> >>There are three basic approaches to doing different langauges in > > computerized text: > >> A/ various adaptations of the 8 bit character set, I.E. the > > ISO-8859-x series. > >> B/ wide characters >> ********This should be how Postgress stores data > > internally.******** > >> C/ Multibyte characters >> ********This is how Postgress should default to sending data OUT > > of the application, > >> i.e. to the display or the web, or other system > > applications******** > > SQL has a system for defining character set specifications, collations > and > such (per column/literal in some cases). We should probably look at it > before making decisions on how to do things. > > > ---------------------------(end of broadcast)--------------------------- > TIP 9: the planner will ignore your desire to choose an index scan if your > joining column's datatypes do not match >
Dennis Gearon wrote: > I agree with all of that except for one caveat: > > all my reading, and just general off the cuff thinking, says that > processing variable width characters SIGNIFICANTLY slows an > application. It seems better to PROCESS fixed width characters (1,2,4 > byte), and TRANSMIT variable width characters (avoiding the null > problem.) I can and have solved that problem. If you can assume utf-8 encoding then there are available to you a bunch o tricks that takes this problem away. The other problem with memory (and hence cache) utilization of a wide char only solution it far more significant. Cache effects are the primary killer for performance in an app like a database. Anyhow, before making any "decisions" one should do a bunch of analysis. Cheers G
I agree, mostly. In the case of a database, I would bet that the INTERNAL, IN-APPLICATION processing
FAAAAAAAAAAARRRRRRRRRRRexceeds that of sending and receiving it.
i.e. comparisons, sorts, triggers, indexes, views, functions, logging to tables, ordering by,
grouping, etc.
except backups, restores, logging to text files (these would be good in UTF8)
Bruce Momjian wrote:
> I think the question is how often are you passing data around/storing it
> _in_ your application and how often are you processing it.
>
> ---------------------------------------------------------------------------
>
> Dennis Gearon wrote:
>
>>I agree with all of that except for one caveat:
>>
>> all my reading, and just general off the cuff thinking, says that processing variable width characters
SIGNIFICANTLYslows an application. It seems better to PROCESS fixed width characters (1,2,4 byte), and TRANSMIT
variablewidth characters (avoiding the null problem.)
>>
>>Gianni Mariani wrote:
>>
>>
>>>Dennis Gearon wrote:
>>>
>>>
>>>>Got a link to that section of the standard, or better yet, to a
>>>>'interpreted' version of the standard? :-)
>>>>
>>>>Stephan Szabo wrote:
>>>>
>>>>
>>>>>On Wed, 13 Aug 2003, Dennis Gearon wrote:
>>>>>
>>>>>
>>>>>
>>>>>>Dennis Bj?rklund wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>>In the future we need indexes that depend on the locale (and a lot
>>>>>>>of other changes).
>>>>>>>
>>>>>>
>>>>>>I agree. I've been looking at the web on this subject a lot lately. I
>>>>>>am **NOT** a microslop fan, but SQL-SERVER even lets a user define a
>>>>>>language(maybe encoding) down to the column level!
>>>>>>
>>>>>>I've been reading on GNU-C and on languages, encoding, and
>>>>>>localization.
>>>>>>
>>>>>>http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper-1.html
>>>>>>
>>>>>>http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2366,1222,00.html
>>>>>>
>>>>>>
>>>>>>
>>>>>>There are three basic approaches to doing different langauges in
>>>>>>computerized text:
>>>>>>
>>>>>> A/ various adaptations of the 8 bit character set, I.E. the
>>>>>>ISO-8859-x series.
>>>>>> B/ wide characters
>>>>>> ********This should be how Postgress stores data internally.********
>>>>>> C/ Multibyte characters
>>>>>> ********This is how Postgress should default to sending data OUT
>>>>>>of the application,
>>>>>> i.e. to the display or the web, or other system
>>>>>>applications********
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>SQL has a system for defining character set specifications,
>>>>>collations and
>>>>>such (per column/literal in some cases). We should probably look at it
>>>>>before making decisions on how to do things.
>>>>
>>>>
>>>I thought UNIX (SCOTM) systems also had a way of being able to define
>>>collation order.
>>>
>>>see:
>>> ftp://dkuug.dk/i18n/WG15-collection/locales
>>>
>>>for a collection of all ISO standardized locales (the WG15 ISO work
>>>group's stuff).
>>>
>>>Do a "man localedef" on most Linuxen or UNIXen.
>>>
>>>As for wide characters vs multibyte, there is no clear winner. The
>>>right answer DEPENDS on the situation.
>>>
>>>Wide characters on some platforms are 16 bit which means that when you
>>>do Unicode you'll still have problems with surrogate pairs (meaning that
>>>it's still multi (wide) char) so you still have all the problems of
>>>multi-byte encodings.
>>>
>>>You could decide to process everything in a PG specific 4 byte wide char
>>>and do all text in Unicode but the overhead in processing 4 times the
>>>data is quite significant. The other option is to store all data in
>>>utf-8 and have all text code become utf-8 aware.
>>>
>>>I have found in practice that the utf-8 option is significantly easier
>>>to implement, 100% Unicode compliant and the best performer (because of
>>>reduced memory requirements).
>>>The Posix API's for locales are not very good for modern day programs,
>>>I'm not sure where the "mbr*" and the "wcr*" apis are in the
>>>standardization process but if these are not well supported, you're on
>>>your own and will need to implement similar functionality from scratch
>>>and for that matter, the collation functions all operate on a "current"
>>>locate which is really difficult to work with on multi-locale applications.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>---------------------------(end of broadcast)---------------------------
>>>TIP 8: explain analyze is your friend
>>>
>>
>>
>>---------------------------(end of broadcast)---------------------------
>>TIP 7: don't forget to increase your free space map settings
>>
>
>
How did you solve the problem .......... :-) Gianni Mariani wrote: > Dennis Gearon wrote: > >> I agree with all of that except for one caveat: >> >> all my reading, and just general off the cuff thinking, says that >> processing variable width characters SIGNIFICANTLY slows an >> application. It seems better to PROCESS fixed width characters (1,2,4 >> byte), and TRANSMIT variable width characters (avoiding the null >> problem.) > > > > I can and have solved that problem. If you can assume utf-8 encoding > then there are available to you a bunch o tricks that takes this problem > away. > > The other problem with memory (and hence cache) utilization of a wide > char only solution it far more significant. > Cache effects are the primary killer for performance in an app like a > database. > > Anyhow, before making any "decisions" one should do a bunch of analysis. > > Cheers > G > > > >
Perhaps the only way to get around the cache problem is to use an ISO-8859-x 8bit character set, but to have per table, orper column encoding attributes. And of course, ways to access what those are, in the Postgres API. Good for speed, butnot for easy storing of multiple language/encodings per column/table. Gianni Mariani wrote: > Dennis Gearon wrote: > >> I agree with all of that except for one caveat: >> >> all my reading, and just general off the cuff thinking, says that >> processing variable width characters SIGNIFICANTLY slows an >> application. It seems better to PROCESS fixed width characters (1,2,4 >> byte), and TRANSMIT variable width characters (avoiding the null >> problem.) > > > > I can and have solved that problem. If you can assume utf-8 encoding > then there are available to you a bunch o tricks that takes this problem > away. > > The other problem with memory (and hence cache) utilization of a wide > char only solution it far more significant. > Cache effects are the primary killer for performance in an app like a > database. > > Anyhow, before making any "decisions" one should do a bunch of analysis. > > Cheers > G > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org >
Dennis Gearon wrote: > How did you solve the problem .......... :-) inlining - most chars are just ascii and there are trivial optimizations that can lead to just as fast as moving 4x the data around.
Ok, thanks for all the discussion followed, vey educational :-)) But nobody really followed up my question :-( For example, you have a table that is displayed in the browser. You want to let the user do sorting on one or multible columns, including those which contain localized strings. If the db supports sorting for multi-linguages, you can retreive all the rows and do "ORDER BY" on the columns directly. But if db doesn't support that, in Java, you will have to retrieve all the rows first, sort the objects on multiple columnes listed in the "ORDER BY" in java. It is much slower than the previous one. My problem is that if initdb is done with en_US, if a customer in Japan request the page with that sorted table, the text is not sorted in a Japanese one. Then I have a problem. Any suggestions on that ?? Dennis Gearon wrote: > I agree, mostly. In the case of a database, I would bet that the > INTERNAL, IN-APPLICATION processing FAAAAAAAAAAARRRRRRRRRRR exceeds that > of sending and receiving it. > > i.e. comparisons, sorts, triggers, indexes, views, functions, > logging to tables, ordering by, > grouping, etc. > > except backups, restores, logging to text files (these would be good > in UTF8) > > Bruce Momjian wrote: > >> I think the question is how often are you passing data around/storing it >> _in_ your application and how often are you processing it. >> >> --------------------------------------------------------------------------- >> >> >> Dennis Gearon wrote: >> >>> I agree with all of that except for one caveat: >>> >>> all my reading, and just general off the cuff thinking, says that >>> processing variable width characters SIGNIFICANTLY slows an >>> application. It seems better to PROCESS fixed width characters (1,2,4 >>> byte), and TRANSMIT variable width characters (avoiding the null >>> problem.) >>> >>> Gianni Mariani wrote: >>> >>> >>>> Dennis Gearon wrote: >>>> >>>> >>>>> Got a link to that section of the standard, or better yet, to a >>>>> 'interpreted' version of the standard? :-) >>>>> >>>>> Stephan Szabo wrote: >>>>> >>>>> >>>>>> On Wed, 13 Aug 2003, Dennis Gearon wrote: >>>>>> >>>>>> >>>>>> >>>>>>> Dennis Bj?rklund wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>>> In the future we need indexes that depend on the locale (and a >>>>>>>> lot of other changes). >>>>>>>> >>>>>>> >>>>>>> I agree. I've been looking at the web on this subject a lot >>>>>>> lately. I >>>>>>> am **NOT** a microslop fan, but SQL-SERVER even lets a user define a >>>>>>> language(maybe encoding) down to the column level! >>>>>>> >>>>>>> I've been reading on GNU-C and on languages, encoding, and >>>>>>> localization. >>>>>>> >>>>>>> http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper-1.html >>>>>>> >>>>>>> http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2366,1222,00.html >>>>>>> >>>>>>> >>>>>>> >>>>>>> There are three basic approaches to doing different langauges in >>>>>>> computerized text: >>>>>>> >>>>>>> A/ various adaptations of the 8 bit character set, I.E. the >>>>>>> ISO-8859-x series. >>>>>>> B/ wide characters >>>>>>> ********This should be how Postgress stores data >>>>>>> internally.******** >>>>>>> C/ Multibyte characters >>>>>>> ********This is how Postgress should default to sending data >>>>>>> OUT of the application, >>>>>>> i.e. to the display or the web, or other system >>>>>>> applications******** >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> SQL has a system for defining character set specifications, >>>>>> collations and >>>>>> such (per column/literal in some cases). We should probably look >>>>>> at it >>>>>> before making decisions on how to do things. >>>>> >>>>> >>>>> >>>> I thought UNIX (SCOTM) systems also had a way of being able to >>>> define collation order. >>>> >>>> see: >>>> ftp://dkuug.dk/i18n/WG15-collection/locales >>>> >>>> for a collection of all ISO standardized locales (the WG15 ISO work >>>> group's stuff). >>>> >>>> Do a "man localedef" on most Linuxen or UNIXen. >>>> >>>> As for wide characters vs multibyte, there is no clear winner. The >>>> right answer DEPENDS on the situation. >>>> >>>> Wide characters on some platforms are 16 bit which means that when >>>> you do Unicode you'll still have problems with surrogate pairs >>>> (meaning that it's still multi (wide) char) so you still have all >>>> the problems of multi-byte encodings. >>>> >>>> You could decide to process everything in a PG specific 4 byte wide >>>> char and do all text in Unicode but the overhead in processing 4 >>>> times the data is quite significant. The other option is to store >>>> all data in utf-8 and have all text code become utf-8 aware. >>>> >>>> I have found in practice that the utf-8 option is significantly >>>> easier to implement, 100% Unicode compliant and the best performer >>>> (because of reduced memory requirements). >>>> The Posix API's for locales are not very good for modern day >>>> programs, I'm not sure where the "mbr*" and the "wcr*" apis are in >>>> the standardization process but if these are not well supported, >>>> you're on your own and will need to implement similar functionality >>>> from scratch and for that matter, the collation functions all >>>> operate on a "current" locate which is really difficult to work with >>>> on multi-locale applications. >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> ---------------------------(end of >>>> broadcast)--------------------------- >>>> TIP 8: explain analyze is your friend >>>> >>> >>> >>> ---------------------------(end of broadcast)--------------------------- >>> TIP 7: don't forget to increase your free space map settings >>> >> >> > > > ---------------------------(end of broadcast)--------------------------- > TIP 9: the planner will ignore your desire to choose an index scan if your > joining column's datatypes do not match --
From what I've read, the db will ONLY sort on the language it was 'initdb'd on. I guess the 'C' locale should would sortit sort of, in other languages. Kathy zhu wrote: > Ok, thanks for all the discussion followed, vey educational :-)) > But nobody really followed up my question :-( > > For example, you have a table that is displayed in the browser. You want > to let the user do sorting on one or multible columns, including those > which contain localized strings. > > If the db supports sorting for multi-linguages, you can retreive all the > rows and do "ORDER BY" on the columns directly. > > But if db doesn't support that, in Java, you will have to retrieve all > the rows first, sort the objects on multiple columnes listed in the > "ORDER BY" in java. It is much slower than the previous one. > > My problem is that if initdb is done with en_US, if a customer in Japan > request the page with that sorted table, the text is not sorted in a > Japanese one. Then I have a problem. > > Any suggestions on that ?? > > > Dennis Gearon wrote: > >> I agree, mostly. In the case of a database, I would bet that the >> INTERNAL, IN-APPLICATION processing FAAAAAAAAAAARRRRRRRRRRR exceeds >> that of sending and receiving it. >> >> i.e. comparisons, sorts, triggers, indexes, views, functions, >> logging to tables, ordering by, >> grouping, etc. >> >> except backups, restores, logging to text files (these would be >> good in UTF8) >> >> Bruce Momjian wrote: >> >>> I think the question is how often are you passing data around/storing it >>> _in_ your application and how often are you processing it. >>> >>> --------------------------------------------------------------------------- >>> >>> >>> Dennis Gearon wrote: >>> >>>> I agree with all of that except for one caveat: >>>> >>>> all my reading, and just general off the cuff thinking, says >>>> that processing variable width characters SIGNIFICANTLY slows an >>>> application. It seems better to PROCESS fixed width characters >>>> (1,2,4 byte), and TRANSMIT variable width characters (avoiding the >>>> null problem.) >>>> >>>> Gianni Mariani wrote: >>>> >>>> >>>>> Dennis Gearon wrote: >>>>> >>>>> >>>>>> Got a link to that section of the standard, or better yet, to a >>>>>> 'interpreted' version of the standard? :-) >>>>>> >>>>>> Stephan Szabo wrote: >>>>>> >>>>>> >>>>>>> On Wed, 13 Aug 2003, Dennis Gearon wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Dennis Bj?rklund wrote: >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>> In the future we need indexes that depend on the locale (and a >>>>>>>>> lot of other changes). >>>>>>>>> >>>>>>>> >>>>>>>> I agree. I've been looking at the web on this subject a lot >>>>>>>> lately. I >>>>>>>> am **NOT** a microslop fan, but SQL-SERVER even lets a user >>>>>>>> define a >>>>>>>> language(maybe encoding) down to the column level! >>>>>>>> >>>>>>>> I've been reading on GNU-C and on languages, encoding, and >>>>>>>> localization. >>>>>>>> >>>>>>>> http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper-1.html >>>>>>>> >>>>>>>> http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2366,1222,00.html >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> There are three basic approaches to doing different langauges in >>>>>>>> computerized text: >>>>>>>> >>>>>>>> A/ various adaptations of the 8 bit character set, I.E. the >>>>>>>> ISO-8859-x series. >>>>>>>> B/ wide characters >>>>>>>> ********This should be how Postgress stores data >>>>>>>> internally.******** >>>>>>>> C/ Multibyte characters >>>>>>>> ********This is how Postgress should default to sending data >>>>>>>> OUT of the application, >>>>>>>> i.e. to the display or the web, or other system >>>>>>>> applications******** >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> SQL has a system for defining character set specifications, >>>>>>> collations and >>>>>>> such (per column/literal in some cases). We should probably look >>>>>>> at it >>>>>>> before making decisions on how to do things. >>>>>> >>>>>> >>>>>> >>>>>> >>>>> I thought UNIX (SCOTM) systems also had a way of being able to >>>>> define collation order. >>>>> >>>>> see: >>>>> ftp://dkuug.dk/i18n/WG15-collection/locales >>>>> >>>>> for a collection of all ISO standardized locales (the WG15 ISO work >>>>> group's stuff). >>>>> >>>>> Do a "man localedef" on most Linuxen or UNIXen. >>>>> >>>>> As for wide characters vs multibyte, there is no clear winner. The >>>>> right answer DEPENDS on the situation. >>>>> >>>>> Wide characters on some platforms are 16 bit which means that when >>>>> you do Unicode you'll still have problems with surrogate pairs >>>>> (meaning that it's still multi (wide) char) so you still have all >>>>> the problems of multi-byte encodings. >>>>> >>>>> You could decide to process everything in a PG specific 4 byte wide >>>>> char and do all text in Unicode but the overhead in processing 4 >>>>> times the data is quite significant. The other option is to store >>>>> all data in utf-8 and have all text code become utf-8 aware. >>>>> >>>>> I have found in practice that the utf-8 option is significantly >>>>> easier to implement, 100% Unicode compliant and the best performer >>>>> (because of reduced memory requirements). >>>>> The Posix API's for locales are not very good for modern day >>>>> programs, I'm not sure where the "mbr*" and the "wcr*" apis are in >>>>> the standardization process but if these are not well supported, >>>>> you're on your own and will need to implement similar functionality >>>>> from scratch and for that matter, the collation functions all >>>>> operate on a "current" locate which is really difficult to work >>>>> with on multi-locale applications. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> ---------------------------(end of >>>>> broadcast)--------------------------- >>>>> TIP 8: explain analyze is your friend >>>>> >>>> >>>> >>>> ---------------------------(end of >>>> broadcast)--------------------------- >>>> TIP 7: don't forget to increase your free space map settings >>>> >>> >>> >> >> >> ---------------------------(end of broadcast)--------------------------- >> TIP 9: the planner will ignore your desire to choose an index scan if >> your >> joining column's datatypes do not match > > >
When I said use en_US as collate, I meant that you language set fall into "Western European" group, another word "Latin1 General" collate, still as Dennis Björklund pointed that Swedish has different sorting rules, ( That's why I guess they have separate Swedish collate ) Generally speaking if you language set is unlimited you effectively stuck? with sorting on client side by using particular language rules. So then use 'C' collate for DB, I do not know what kind of encoding will be good for you tho, Unicode??. So you can sort on a client using xsl:sort and specifing language or any other means that you feel comfortable with. Or just use binary sorting rules, that what 'C' collate does. Choices, choices... -----Original Message----- From: Kathy zhu [mailto:Kathy.zhu@Sun.COM] Sent: Wednesday, August 13, 2003 2:13 PM To: gearond@cvc.net Cc: Bruce Momjian; Gianni Mariani; pgsql-general@postgresql.org Subject: Re: [GENERAL] Sorting Problem Ok, thanks for all the discussion followed, vey educational :-)) But nobody really followed up my question :-( For example, you have a table that is displayed in the browser. You want to let the user do sorting on one or multible columns, including those which contain localized strings. If the db supports sorting for multi-linguages, you can retreive all the rows and do "ORDER BY" on the columns directly. But if db doesn't support that, in Java, you will have to retrieve all the rows first, sort the objects on multiple columnes listed in the "ORDER BY" in java. It is much slower than the previous one. My problem is that if initdb is done with en_US, if a customer in Japan request the page with that sorted table, the text is not sorted in a Japanese one. Then I have a problem. Any suggestions on that ?? Dennis Gearon wrote: > I agree, mostly. In the case of a database, I would bet that the > INTERNAL, IN-APPLICATION processing FAAAAAAAAAAARRRRRRRRRRR exceeds that > of sending and receiving it. > > i.e. comparisons, sorts, triggers, indexes, views, functions, > logging to tables, ordering by, > grouping, etc. > > except backups, restores, logging to text files (these would be good > in UTF8) > > Bruce Momjian wrote: > >> I think the question is how often are you passing data around/storing it >> _in_ your application and how often are you processing it. >> >> ------------------------------------------------------------------------ --- >> >> >> Dennis Gearon wrote: >> >>> I agree with all of that except for one caveat: >>> >>> all my reading, and just general off the cuff thinking, says that >>> processing variable width characters SIGNIFICANTLY slows an >>> application. It seems better to PROCESS fixed width characters (1,2,4 >>> byte), and TRANSMIT variable width characters (avoiding the null >>> problem.) >>> >>> Gianni Mariani wrote: >>> >>> >>>> Dennis Gearon wrote: >>>> >>>> >>>>> Got a link to that section of the standard, or better yet, to a >>>>> 'interpreted' version of the standard? :-) >>>>> >>>>> Stephan Szabo wrote: >>>>> >>>>> >>>>>> On Wed, 13 Aug 2003, Dennis Gearon wrote: >>>>>> >>>>>> >>>>>> >>>>>>> Dennis Bj?rklund wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>>> In the future we need indexes that depend on the locale (and a >>>>>>>> lot of other changes). >>>>>>>> >>>>>>> >>>>>>> I agree. I've been looking at the web on this subject a lot >>>>>>> lately. I >>>>>>> am **NOT** a microslop fan, but SQL-SERVER even lets a user define a >>>>>>> language(maybe encoding) down to the column level! >>>>>>> >>>>>>> I've been reading on GNU-C and on languages, encoding, and >>>>>>> localization. >>>>>>> >>>>>>> http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper- 1.html >>>>>>> >>>>>>> http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2 366,1222,00.html >>>>>>> >>>>>>> >>>>>>> >>>>>>> There are three basic approaches to doing different langauges in >>>>>>> computerized text: >>>>>>> >>>>>>> A/ various adaptations of the 8 bit character set, I.E. the >>>>>>> ISO-8859-x series. >>>>>>> B/ wide characters >>>>>>> ********This should be how Postgress stores data >>>>>>> internally.******** >>>>>>> C/ Multibyte characters >>>>>>> ********This is how Postgress should default to sending data >>>>>>> OUT of the application, >>>>>>> i.e. to the display or the web, or other system >>>>>>> applications******** >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> SQL has a system for defining character set specifications, >>>>>> collations and >>>>>> such (per column/literal in some cases). We should probably look >>>>>> at it >>>>>> before making decisions on how to do things. >>>>> >>>>> >>>>> >>>> I thought UNIX (SCOTM) systems also had a way of being able to >>>> define collation order. >>>> >>>> see: >>>> ftp://dkuug.dk/i18n/WG15-collection/locales >>>> >>>> for a collection of all ISO standardized locales (the WG15 ISO work >>>> group's stuff). >>>> >>>> Do a "man localedef" on most Linuxen or UNIXen. >>>> >>>> As for wide characters vs multibyte, there is no clear winner. The >>>> right answer DEPENDS on the situation. >>>> >>>> Wide characters on some platforms are 16 bit which means that when >>>> you do Unicode you'll still have problems with surrogate pairs >>>> (meaning that it's still multi (wide) char) so you still have all >>>> the problems of multi-byte encodings. >>>> >>>> You could decide to process everything in a PG specific 4 byte wide >>>> char and do all text in Unicode but the overhead in processing 4 >>>> times the data is quite significant. The other option is to store >>>> all data in utf-8 and have all text code become utf-8 aware. >>>> >>>> I have found in practice that the utf-8 option is significantly >>>> easier to implement, 100% Unicode compliant and the best performer >>>> (because of reduced memory requirements). >>>> The Posix API's for locales are not very good for modern day >>>> programs, I'm not sure where the "mbr*" and the "wcr*" apis are in >>>> the standardization process but if these are not well supported, >>>> you're on your own and will need to implement similar functionality >>>> from scratch and for that matter, the collation functions all >>>> operate on a "current" locate which is really difficult to work with >>>> on multi-locale applications. >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> ---------------------------(end of >>>> broadcast)--------------------------- >>>> TIP 8: explain analyze is your friend >>>> >>> >>> >>> ---------------------------(end of broadcast)--------------------------- >>> TIP 7: don't forget to increase your free space map settings >>> >> >> > > > ---------------------------(end of broadcast)--------------------------- > TIP 9: the planner will ignore your desire to choose an index scan if your > joining column's datatypes do not match -- ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
On Wed, Aug 13, 2003 at 11:33:31AM -0700, Dennis Gearon wrote: > Perhaps the only way to get around the cache problem is to use an > ISO-8859-x 8bit character set, but to have per table, or per column > encoding attributes. And of course, ways to access what those are, in the > Postgres API. Good for speed, but not for easy storing of multiple > language/encodings per column/table. Well, each column will have to have a native encoding/collation order. This is the one stored on disk and the one used for indexes. Remember, if your index is collated by en_US and your query asks for nl_NL, you can't use your query for sorting the result. I guess you could have the same column indexed twice with the different collation orders. -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > "All that is needed for the forces of evil to triumph is for enough good > men to do nothing." - Edmond Burke > "The penalty good people pay for not being interested in politics is to be > governed by people worse than themselves." - Plato
Вложения
Dennis Gearon writes: > If we really want to do it, we won't have to do the grunt work ourselves, just the tie-in, and Postgres specific implementation: > > http://www.unicode.org/reports/tr10/ It's already in the works. -- Peter Eisentraut peter_e@gmx.net
Peter Eisentraut <peter_e@gmx.net> writes:
> It's already in the works.
Oh? Please clue us in, if there's work going on that we don't know
about. Otherwise someone might be duplicating effort.
regards, tom lane
Is there a list on this, that I could be part of ? Peter Eisentraut wrote: > Dennis Gearon writes: > > >>If we really want to do it, we won't have to do the grunt work ourselves, just the tie-in, and Postgres specific implementation: >> >> http://www.unicode.org/reports/tr10/ > > > It's already in the works. >