maria-developers team mailing list archive

[Pavel Ivanov <pivanof@xxxxxxxxxx>]

> Alternatively, you can try to link your plugin explicitly with
> libmyisam.a

Won't this create two copies of libmyisam.a in memory (each one
working with it's own set of static variables), and there'll be a
danger of calling functions from different libraries with the same set
of dynamically allocated data?


Pavel


On Thu, Dec 5, 2013 at 10:06 AM, Sergei Golubchik <serg@xxxxxxxxxxx> wrote:
> Hi, AugustQ!
>
> On Dec 05, AugustQ wrote:
>>
>> just one question:
>> I have a simple plugin (a minimal storage engine) that does not load.
>> When I try to load it I get this error-message:
>>
>> MariaDB [(none)]> install plugin dummy soname 'ha_dummy';
>> ERROR 1126 (HY000): Can't open shared library
>> '/home/august/MariaDB/pgm/lib/plugin/ha_dummy.so' (errno: 2 undefined
>> symbol: _ZN9ha_myisam5cloneEPKcP11st_mem_root)
>>
>> Can you please give me a tip. Thanks.
>>
>> Environment is MariaDB 10.0.4.
>>
>> The same code works without any problems in MySQL (5.5.8 - just for a
>> test).
>
> This happens because in MariaDB statically linked plugins don't export
> all their symbols. This helps to avoid name clashes with dynamically
> loaded plugins (like, when InnoDB is loaded and XtraDB is compiled in).
> Unlike MySQL we have a lot more of community developed storage engines,
> and we have to take these issues seriously.
>
> Because of that, the symbol _ZN9ha_myisam5cloneEPKcP11st_mem_root is
> local in MariaDB, and your plugin doesn't see it. In MySQL this symbol
> is global.
>
> I'll see if I can remove this.
>
> Alternatively, you can try to link your plugin explicitly with
> libmyisam.a
>
> Regards,
> Sergei
>
>
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