Re: bp with empty char/varchar column broken

> On Nov 21, 2014, at 5:58 AM, Frediano Ziglio <[email protected]> wrote:
> 
> 2014-11-20 19:53 GMT+00:00 Craig A. Berry <[email protected]>:
>> The following worked in 0.91 but is broken as of branch-0_92-839-gd788046.  If we bulk out a table with an empty (but not NULL) char or varchar column that is less than 256 bytes long, 256 spaces get written to the output file for that column.  Which then causes an overflow error if you try to bulk it back in.
> 

> Quite strange. Why does it happen only for empty strings? Should even
> happen with small ones. The function has to pad or not based on type.

The actual length of the string received on the wire is passed as the source length to dbconvert, and dbconvert (usually) uses that as its return value, and that return value is passed to fwrite for moving data to the file.

But if the source length is zero, dbconvert uses the destination length as its return value as long as the destination length is greater than zero.  Since it's now always 256, we get 256 spaces.

> Actually is not clear to me what an empty column should look like in
> the text bcp file.

I'm pretty sure a zero-length column in a bcp file indicates NULL, and one or more spaces indicates empty string and will be trimmed on bulk in.

________________________________________
Craig A. Berry
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"... getting out of a sonnet is much more
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