[freetds] bcp text upload trace

Thompson, Bill D (London) bill_d_thompson at ml.com
Fri Jun 11 06:47:45 EDT 2004


James,

Further to my last email, the tcpdump does not throw up anything much that
we didn't know before.

For bulkcopy to SQL server, TEXT data is being sent to SQL server in the way
that we previously understood and supported.
First we send a COLMETADATA/RESULTS message 0x81, where the text column is
described in the same way as any other column type.
Then we send a ROW message 0xd1, and the text data is formatted as any other
column type.

Two new things we didn't know before:

1) The client queries the server to see what level of bcp compatibility it
supports by exec-ing the undocumented stored procedure sp_bcp_dbcmptlevel
<database>.
    On my SQL2K servers this returns "80". presumably bcp is backwards
compatible to SQL server 7 or 6.5 or 6.0
    I'd be interested to see a tcpdump when bcp is invoked with -V 6.5 (see
BOL)

2) The client issues another undocumented procedure sp_tablecollations
'testdb..text_test' to get the SQL server description of the collations in
the table.
    This is used to build the "insert bulk" statement . I guess we may find
doing this useful here, or elsewhere...

Bill

> -----Original Message-----
> From:	Lowden, James K [SMTP:LowdenJK at bernstein.com]
> Sent:	10 June 2004 21:57
> To:	TDS Development Group
> Subject:	[freetds] bcp text upload trace
> 
> Our BCP implementation doesn't do TEXT columns.  Neither does it complain;
> it just hangs because the server doesn't respond.  
> 
> For your enjoyment, attached is tcpdump output of an upload to a table
> having a single column, of type TEXT.  The tools used were:
> 
> $ bcp -v
> BCP - Bulk Copy Program for Microsoft SQL Server.
> Copyright (c) 1991-1998, Microsoft Corp. All Rights Reserved.
> Version: 7.00.623
> 
> $ isql -E -Smpquant -Q"select @@version"
>         --------------------------------
>  Microsoft SQL Server  2000 - 8.00.818 (Intel X86)
>         May 31 2003 16:08:15
>         Copyright (c) 1988-2003 Microsoft Corporation
>         Enterprise Edition on Windows
>          NT 5.0 (Build 2195: Service Pack 3)
> 
> and
> 
> $ windump -w textbcp.tcpdump -xX -s1500 tcp and host mpquant and port 2500
> and host ntc0272
> 
> I thought perhaps we could at least decode what's going on.  That would
> make it easier to add the functionality.  
> 
> Thank you for your kind attention.  
> 
> --jkl
> 
> 
>  <<textbcp.tcpdump.upload.text>> 
> 
> 
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>  << File: textbcp.tcpdump.upload.text >>  << File: ATT2247823.txt >> 

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