On 11/11/09 3:25 PM, Paolo Lunazzi wrote:
> On Wed, Nov 11, 2009 at 4:22 PM, Davi Arnaut<Davi.Arnaut@stripped> wrote:
>>
>> On 11/11/09 9:08 AM, Paolo Lunazzi wrote:
>>>
>>> Hi everybody,
>>> I'm starting to look inside MySQL Internals because I need to write a
>>> little patch to log users access into db.
>>
>> The server already has a few logs:
>>
>> http://dev.mysql.com/doc/refman/5.1/en/server-logs.html
>>
>> What do you have in mind specifically?
>
> General Query Log writes information when clients connect or
> disconnect and it logs each SQL statement received from clients too. I
> want to be able to choose to log all or only information about access
> to db ( timestamp, user, host, db, ...) and I want to be able to do
> that only for some user groups.
Indeed, we don't have this kind of finer grained logging.
> The idea comes from an Italian law that will be in force this December
> that establish to log information about db administrators access. At
> the moment it's possibly to log all or nothing, I think that a
> management more customizable of this kind of logging might be useful
> even in other contexts.
OK, in this case you have two options. You can do post-filtering on the
log tables -- for example, by having a periodic event that scans the log
table and filters the data to another table.
Another option is to implement a new log handler -- if you look at file
sql/log.h, there is a abstract Log_event_handler class that you can
extend to implement a new log target (eg: Log_to_csv_event_handler).
You will probably be interested in the log_general method, where you can
access various information about the current user session (THD). For
some initial fun, you could look around sql/log.cc and play with the
log_general method of the class Log_to_csv_event_handler or
Log_to_file_event_handler. If you know your way around C++, shouldn't be
difficult.
--
Davi Arnaut
