Re: SQLGetData() returns TEXT length minus one on Solaris 64b with SQL Server 2005

2013/2/4 Sebastien FLAESCH <[email protected]>:
> Frediano,
>
> I believe it's related to the client charset conversions...
>
> I did following simple test:
>
> My database collation is CP1252, so to avoid iconv usage, in the ODBC
> data source definition, I have now:
>
> ClientCharset = CP1252
>
> The program uses only pure ASCII chars, so this is ok.
>
> Now there is no more iconv error in the log, and the first call to
> SQLGetData() returns 10000 bytes as expected...
>
> If fact for character data, ODBC returns the char pieces with an
> additional \0 terminator.
>
> So, with a buffer of 4096 bytes:
>
> Call #1 to SQLGetData() returns len=10000 bytes (ok)
> Call #2 to SQLGetData() returns len=5905 bytes
>    there was 5905 bytes left to read, because only 4095 bytes could
>    be written to the buffer, because of additional \0 terminator.
>    10000 - 4095 = 5905 ...
> Call #3 to SQLGetData() returns len=1810 bytes
>     5905 - 4095 = 1810 ...
> Last call: 1810 bytes fit in the 4096 buffer.
>

Well, this is expected. But I don't understand what's going wrong with Solaris.
Could be possible that Solaris do not convert some characters and so
it convert a byte characters to 0 bytes ??
Are you sure that there is only ASCII characters (0-127) ??
Why should Solaris report some warning converting ASCII ??
A dump would be helpful. Send privately to me if it contains sensitive
information.
You could try using libiconv.

> I hope this helps...
>
> Seb
>

Frediano


>
> On 02/03/2013 12:12 PM, Frediano Ziglio wrote:
>> Hi,
>>    where is SQL_DATA_AT_EXEC in your code?
>>
>> Which DM are you using? Is possible that for some reason DM call some
>> additional function to do some checks. This could discovered enabling
>> FreeTDS dump.
>>
>> Quire strange it works correctly on Linux but not on Solaris.
>> Does data contains no-ASCII characters?
>> How long are usually these TEXT fields?
>> Which TDS protocol version are you using?
>> There is a specific getdata test for this stuff and should work.
>>
>> Regards,
>>    Frediano
>>
>> 2013/2/2 Sebastien FLAESCH<[email protected]>:
>>> Hi Frediano,
>>>
>>> FYI, we use a single-byte encoding (LANG=POSIX) ...
>>>
>>> Here is the code we use, nothing particular, this is the same code we
>>> use for different ODBC drivers...
>>>
>>> #define BLOB_BLOCK_SIZE 4096
>>> ....
>>> static SQLRETURN getBlobPieces(SqlStatement * st, SQLUSMALLINT fpos,
>>>                                  SQLSMALLINT ctype, MyLocator * loc,
>>>                                  FILE * out, SQLLEN * plen)
>>> {
>>>       SQLRETURN r = 0;
>>>       char buf[BLOB_BLOCK_SIZE];
>>>       SQLLEN len;
>>>       int i = 0;
>>>       while (1) {
>>>           r = SQLGetData(st->stmtHandle, fpos, ctype,
>>>                          (SQLPOINTER) buf, sizeof(buf),&len);
>>>           if (!SQL_SUCCEEDED(r) || len == 0 || len == SQL_NULL_DATA)
>>>               break;
>>>           if (len>  (SQLLEN) sizeof(buf) || len == SQL_NO_TOTAL)
>>>               len = sizeof(buf);
>>>           /* Char data piece get \0, these must be removed! */
>>>           if (ctype == SQL_C_CHAR) {
>>>               if (buf[len - 1] == '\0') {
>>>                   len--;
>>>               }
>>>           }
>>>           fwrite(buf, 1, len, out);
>>>       }
>>>       *plen = len;
>>>       return r;
>>> }
>>>
>>> Am I missusing SQLGetData()? As you can see, I modify the len after
>>> Does this affect the next call to SQLGetData()?
>>>
>>> Anyway, the INITIAL len returned by SQLGetData() is for sure:
>>>
>>>      (total-bytes - 1)
>>>
>>> When using UTF-8, I get SQL_NO_TOTAL in the first call, but in ASCII,
>>> I get the (total size - 1)...
>>>
>>> Seb
>>>
>>> On 02/02/2013 08:52 AM, Frediano Ziglio wrote:
>>>> Il giorno 31/gen/2013, alle ore 14:28, Sebastien FLAESCH<[email protected]>   ha scritto:
>>>>
>>>>> Hi all,
>>>>>
>>>>> Context:
>>>>>
>>>>> $ uname -a
>>>>> SunOS s64x100 5.10 Generic_120012-14 i86pc i386 i86pc
>>>>>
>>>>> FreeTDS versions tested:
>>>>> - freetds-0.92.dev.20120312
>>>>> - freetds-dev.0.92.377
>>>>>
>>>>> When fetching a TEXT from the database (SQL Server 2005), using SQL_DATA_AT_EXEC,
>>>>> it appears that the SQLGetData() function returns the size of the text data,
>>>>> minus one...
>>>>>
>>>>> I have tested the same FreeTDS version on a Linux 32b, and SQLGetData() returns
>>>>> the correct length as expected...
>>>>>
>>>>
>>>> Strange! How do you read the length?
>>>>
>>>>> I will continue to investigate, but I wanted to ask if this is a know issue.
>>>>>
>>>>> When connecting to SQL Server 2008 R2, this does not occur, because SQLGetData()
>>>>> returns SQL_NO_TOTAL and we fetch text pieces in a different way...
>>>>>
>>>>
>>>> This is done to deal with different encodings.
>>>>
>>>>> Thanks
>>>>> Seb
>>>>
>>>> Frediano
>>>>
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