[unixODBC-support] unicode issues :/ st_fetch/SQLFetch (long truncated DBI attribute LongTruncOk not set and/or LongReadLen too small)

Daniel Kasak d.j.kasak.dk at gmail.com
Sat Mar 7 02:18:02 GMT 2015


OK now I'll withdraw my entire question. I've found that building DBD::ODBC
with unicode support:

perl Makefile.PL -u

 ... fixes the issues I'm seeing with SQL Server. Unfortunately, now
connecting to Netezza is completely broken.

When I call DBI->connect() ... I get an error back:

DBI
connect('DRIVER=NetezzaSQL;server=nz_host;Port=5480;UID=admin;PWD=n3t322a;Database=SYSTEM','admin',...)
failed: [unixODBC]Srtrbtsaeepy

 ... with 2 boxes at the end that I can't seem to copy + paste for some
reason. Also the exact text of the error seems to change with each
connection attempt.

I don't see anything at the database end about an attempted connection. I
guess the Netezza ODBC drivers don't support this setup? Is there anything
I can do to work around this?

ODBC trace:

http://tesla.duckdns.org/downloads/netezza.log

Dan

On Sat, Mar 7, 2015 at 9:55 AM, Daniel Kasak <d.j.kasak.dk at gmail.com> wrote:

> Actually I have to correct myself ... when selecting the entire column at
> once, I *am* getting the correct data, at least as far as Perl is
> concerned. It seems I have multiple bugs ... Gtk3 is not displaying unicode
> stuff correctly. Anyway, the substring() bug remains.
>
> Dan
>
> On Sat, Mar 7, 2015 at 9:26 AM, Daniel Kasak <d.j.kasak.dk at gmail.com>
> wrote:
>
>> Excellent :) Thanks for helping out.
>>
>> Code:
>> http://tesla.duckdns.org/downloads/odbc_test.pl
>>
>> Table DDL:
>> http://tesla.duckdns.org/downloads/DimCustomer.sql
>>
>> Data:
>> http://tesla.duckdns.org/downloads/DimCustomerData.csv
>>
>> If it's easier for you, I can set up port forwarding to my SQL Server
>> instance ( it's purely for testing this kind of thing ). Let me know ...
>>
>> The database is Microsoft's AdventureWorksDW2014 demo database:
>> https://msftdbprodsamples.codeplex.com/releases/view/125550
>>
>> It may ( or may not ) be easier for you to just download that demo - it
>> comes as a SQL Server backup file, and you don't have to mess around with
>> loading the CSV ( I exported it from SQL Server Management Studio ). To be
>> honest, I haven't used SQL Server for about 15 years, so I'm not sure what
>> he easiest way of loading data is these days.
>>
>> If what I'm seeing is correct though, you can define a table with a
>> single nvarchar column, insert any non-ASCII character, as dummy data to
>> trigger this bug.
>>
>> 2 things to note in Linux:
>>
>> 1) If you use a substring() function on the column ( selecting *only* to
>> non-ASCII character ), you'll get zero records back, and the truncation
>> warnings.
>>
>> 2) If you *don't* substring() the column, you get data back, but it's
>> corrupted.
>>
>> In Windows, the above behaves as expected.
>>
>> Let me know if there is anything else you need ...
>>
>> Dan
>>
>> On Sat, Mar 7, 2015 at 12:31 AM, Martin J. Evans <bohica at ntlworld.com>
>> wrote:
>>
>>> On 05/03/15 22:55, Daniel Kasak wrote:
>>>
>>>> I've installed DBD::ODBC from git just now and tested. Same error :/
>>>>
>>>
>>> ok, that rules that out.
>>>
>>> Can you give us a small example bit of perl which demonstrates the
>>> problem.
>>>
>>> The schema for the table would be useful too.
>>>
>>> Martin
>>>
>>>  On Fri, Mar 6, 2015 at 8:06 AM, Daniel Kasak <d.j.kasak.dk at gmail.com
>>>> <mailto:d.j.kasak.dk at gmail.com>> wrote:
>>>>
>>>>     Hi. Thanks for the responses :)
>>>>
>>>>     I'm using DBD::ODBC version 1.50, which is the latest version I see
>>>> on CPAN ( and my cpan client agrees ).
>>>>
>>>>     I'm not using bound input parameters on this particular connection
>>>> - I'm using it on other connections inside the app, but definitely not this
>>>> connection. The window where this particular failure happens is a SQL
>>>> client. Users can enter any SQL they want. I do very limited parsing to
>>>> detect whether they've entered a 'select' query or not. If it's a select,
>>>> the SQL gets passed to Gtk3::Ex::DBI ( which is also my code ) as a
>>>> 'pass-through' query ... in which case no further parsing is done, and
>>>> bound input parameters are not used. The SQL gets executed, and a datasheet
>>>> is populated from the results of the query execution.
>>>>
>>>>     I've just rebooted into Windows ... and yes I have DBD::ODBC
>>>> version 1.50 in Windows too.
>>>>
>>>>     Dan
>>>>
>>>>     On Fri, Mar 6, 2015 at 2:02 AM, Martin J. Evans <
>>>> bohica at ntlworld.com <mailto:bohica at ntlworld.com>> wrote:
>>>>
>>>>         On 05/03/15 13:47, Daniel Kasak wrote:
>>>>
>>>>             Hi all.
>>>>
>>>>             I'm struggling to understand some issues I'm seeing talking
>>>> to SQL Server. I'm pretty sure I've isolated the issue to unixODBC.
>>>>
>>>>             I've loaded by Microsoft's AdventureWorksDW2014 database
>>>> for testing purposes. To give an idea of the data, here's a query I've been
>>>> testing. It fails in Linux, but runs and displays find in Windows:
>>>>
>>>>             http://tesla.duckdns.org/__images/windows_odbc.png <
>>>> http://tesla.duckdns.org/images/windows_odbc.png>
>>>>
>>>>             As you can see, I'm substring-ing out each character ( I'm
>>>> debugging yet other issues ), and also getting hex values for each
>>>> character. Note the 6th character ( column S6 ), with hex value f3 ( column
>>>> H6 ). Also note the complete string at the end.
>>>>
>>>>             ---
>>>>
>>>>             Issue 1)
>>>>
>>>>             http://tesla.duckdns.org/__images/linux_odbc_1.png <
>>>> http://tesla.duckdns.org/images/linux_odbc_1.png>
>>>>
>>>>             Note in this screenshot, the last column - the complete
>>>> string. That doesn't look right. It's difficult to say *why* it doesn't
>>>> look right, but my feeling is that the driver is sending a multibyte
>>>> character, and somewhere along the line it's being interpreted as 2
>>>> single-byte characters.
>>>>
>>>>             Issue 2)
>>>>
>>>>             You might have noticed I'd commented out the expression for
>>>> S6 in the Linux query. If I run the query with the S6 expression, I get an
>>>> empty recordset back, and the following in STDERR:
>>>>
>>>>             DBD::ODBC::st fetchrow_array failed: st_fetch/SQLFetch
>>>> (long truncated DBI attribute LongTruncOk not set and/or LongReadLen too
>>>> small) (SQL-HY000)
>>>>
>>>>             Now ... note that this is a single character ... and that
>>>> things weren't too long when I selected the entire column at once. I've
>>>> tried setting LongReadLen to various large values. That doesn't stop this
>>>> error. If I also set LongTruncOk, the error disappears, *and* I get a
>>>> recordset, but the S6 column is null.
>>>>
>>>>             What's going on here? If this was related to the 1st issue
>>>> ( and I feel it might be ) ... I'd say the driver manager was expecting a
>>>> single byte character only for the entire field, but was receiving a
>>>> multi-byte character.
>>>>
>>>>             ---
>>>>
>>>>             I built unixODBC-2.3.2 with the following configure options:
>>>>                --enable-iconv --disable-drivers --disable-driverc
>>>> --with-iconv-char-enc=UTF8 --with-iconv-ucode-enc=UTF16LE
>>>>
>>>>             I've tested with freetds-0.91, *and* with Microsoft's
>>>> native client for Linux. Interestingly, I get exactly the same behaviour
>>>> with both.
>>>>
>>>>             I've obviously also tested in Windows, which produced the
>>>> 1st screenshot. Based on the fact that it works perfectly in Windows, I'd
>>>> assume Microsoft's drivers, *and* DBD::ODBC, *and* my code are behaving
>>>> well. And based on the fact that both freetds and MS's drivers produce
>>>> exactly the same failure under Linux, I'm guessing the problem lies
>>>> somewhere in unixODBC. I do concede that it's possible that the same bug
>>>> exists in freetds and Microsoft's native client, and that unixODBC is
>>>> completely innocent.
>>>>
>>>>             An odbc trace is at ( pasting it in the message make the
>>>> message too big to post, apparently ):
>>>>             http://tesla.duckdns.org/__downloads/trace.log <
>>>> http://tesla.duckdns.org/downloads/trace.log>
>>>>
>>>>             Note that this will have *two* executions of the query. My
>>>> app 1st executes each query with the filter "where 0=1" ... to analyse the
>>>> columns and decide how to go about things. Then it execute the 'real' query.
>>>>
>>>>             Any help greatly appreciated.
>>>>
>>>>             Dan
>>>>
>>>>
>>>>         Sounds like it could be this bug:
>>>>
>>>>         1.51_3 2015-01-17
>>>>
>>>>            [BUG FIXES]
>>>>
>>>>            RT101579 - using bound input parameters for numeric columns
>>>> (e.g.,
>>>>            SQL_NUMERIC) only works the first time and will quite likey
>>>> fail
>>>>            with "string data, right truncation" on the second and
>>>> subsequent
>>>>            calls to execute. Thanks to Laura Cox for finding.
>>>>
>>>>         What version of DBD::ODBC are you using?
>>>>
>>>>         What does you perl code look like?
>>>>
>>>>         Martin
>>>>
>>>>
>>>>         _________________________________________________
>>>>         unixODBC-support mailing list
>>>>         unixODBC-support at mailman.__unixodbc.org <mailto:
>>>> unixODBC-support at mailman.unixodbc.org>
>>>>         http://mailman.unixodbc.org/__mailman/listinfo/unixodbc-__
>>>> support <http://mailman.unixodbc.org/mailman/listinfo/unixodbc-support>
>>>>
>>>>
>>>>
>>>>
>>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.unixodbc.org/pipermail/unixodbc-support/attachments/20150307/e4501c61/attachment-0001.html>


More information about the unixODBC-support mailing list