Hello,
I have a working plugin which I'll push to Launchpad soon. I have a question
about using the update_func_arg of class sys_var_std_string to create a dynamic
variable. My plugin's class has a file descriptor to the open query log file,
but the update function can't access it because it doesn't receive a pointer to
the plugin's class. I can make the file descriptor var global in my plugin's
namespace, but I'd like to keep everything inside the class. Is this possible?
I tried hacking and casting and passing a pointer to a non-static member
function of the class, but I couldn't get that to work. My update function is
currently:
bool update_file(Session *, set_var *var)
{
const char *new_file= var->value->str_value.ptr();
if (fd)
close(fd);
fd= open_log_file(new_file);
if (fd < 0)
return false; // error
sysvar_file= new_file;
return false; // success
}
fd and sysvar_file are global in the plugin's namespace. Does that code look
correct? (It work in fact.) I don't think any other modules use the update
func feature, so I don't have a basis for comparison.
Thanks,
Daniel
Le 26 avr. 2011 à 08:46, Monty Taylor a écrit :
> I'm also in favor of this - but I have two additional suggestions:
>
> Just make a new plugin - slow_query_log
>
> Look in to using the new Event plugin type, rather than the Logging
> plugin type. (I believe Mark has been working on converting the syslog
> logger over to use this) It's a better/more flexible interface.
>
> Go for it!
>
> Monty
>
>
> On 04/25/2011 09:34 PM, Daniel Nichter wrote:
>> Hello,
>>
>> I'd like to propose a new logging_query plugin. The plugin is still, in
>> Mark's words from 2008, "currently very rough and crude: logging far too
>> much, in an awkward log format"
>> (http://fallenpegasus.livejournal.com/759373.html). And
>> as https://bugs.launchpad.net/drizzle/+bug/723915 notes, it's not tested
>> either.
>>
>> I think the CSV format will not serve users well in the long run for the
>> following reasons.
>>
>> 1) Without a header there's no way to know which values are what.
>> Andrew mentioned via a comment to another blog post that this may be
>> added but there are still other problems...
>>
>> 2) When should the header be printed? Probably every time the log is
>> opened. Once would surely not be enough. In any case, chances are that
>> whenever or wherever it's printed it will get lost in a big log file.
>> So either a user will have to search for it by eye, or a log parsing
>> tool will have to search for it before it can know how to parse the log.
>>
>> 3) Queries are flattened which may not be desirable in all cases.
>> Sometimes we want to get the original query from the log. If a value
>> has a line in it like col="line1
>> line2"
>> then this will be lost.
>>
>> 4) CSV requires quoting and escaping which, for one, adds overhead to
>> the plugin and, for two, makes the job of a log parsing tool more difficult.
>>
>> 5) I'm sure that more information will be added to the Drizzle query log
>> over time, just as more was added to the MySQL slow log. This will make
>> the CSV format even more unwieldy and quite possibly variable making the
>> issue of headers even more troublesome.
>>
>> 6) Query logs are basically useless without a tool to parse them. The
>> currently log format will need its own tool, but if it used the MySQL
>> slow log format, then there are already several tools that could parse it.
>>
>> So I propose to rewrite logging_query in the style of the MySQL slow log
>> format but without all its gotchas, fluff and other stuff that make
>> parsing it a real pita. If Drizzle is not fondly attached to
>> logging_query in its current state, then I would like to rewrite it.
>>
>> Yay, nay?
>>
>> -Daniel
>>
>>
>>
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