Bug#917303: Request for help with MariaDB 10.3 / libdbd-mysql-perl packaging

[Georg Richter]

Hi,

the zerofill test fails, since dbd-mysql binds a buffer with
buffer_length=1, so MariaDB Connector/C can't add leading zeros and just
returns 1.

Perl seems to retrieve the information from metadata after
mysql_stmt_store_result() call. According to the documentation (
https://dev.mysql.com/doc/refman/8.0/en/mysql-stmt-attr-set.html) you have
to call mysql_stmt_attr_set(stmt, STMT_ATTR_UPDATE_MAX_LENGTH, &value) to
force mysql_stmt_store_result to update the max_length value in metadata -
however its not set and therefore Connector/C doesn't return expected value.

The correct behavior would be to check the metadata after
mysql_stmt_prepare() and calculate the buffer_size or to force Connector/C
to calculate the size via STMT_ATTR_UPDATE_MAX_LENGTH. I would prefer the
latter one, since in some cases metadata after prepare can't be calculated
correctly, e.g. for a "SELECT ? FROM DUAL"

/Georg

On Fri, Dec 28, 2018 at 1:31 PM gregor herrmann <gregoa at debian.org> wrote:

> On Fri, 28 Dec 2018 11:27:04 +0200, Otto Kekäläinen wrote:
>
> > pe 28. jouluk. 2018 klo 11.09 Georg Richter (georg at mariadb.com)
> kirjoitti:
> > > no clue about dbd-mysql - we reported several bugs (and sent
> > > fixes), but didn't get feedback since more than a year. Why don't
> > > you ship DBD-mariadb instead?
> > Gregor Hermann, do you want to switch to DBD-mariadb instead?
>
> DBD-mariadb is in the archive since a couple of months:
> https://tracker.debian.org/libdbd-mariadb-perl
>
> Unfortunately, it's not a 1:1 replacement for DBD-mysql and many user
> will want to continue using the latter in their existing codebase.
>
> Georg, maybe you can give us pointers to the bugs and fixes you
> mentioned above?
>
>
> Cheers,
> gregor
>
> --
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-- 
Georg Richter, Senior Software Engineer
MariaDB Corporation Ab
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