Re: Backend Stats Enhancement Request

Thanks for the feedback Tom. An initial patch for this has been posted
to pgsql-patches.

Cheers,
T

Tom Lane wrote:
> Thomas Lee <tom(at)vector-seven(dot)com> writes:
>
>> How does this sound:
>>
>
>
>> * A new GUC variable -- "activity_message_size" -- will be introduced
>>
>
> Well, "message" doesn't seem quite le mot juste to me for a column that
> is displaying a SQL command. Usually we'd use "statement", "command",
> or "query" to refer to one of those things. Since the relevant column
> of pg_stat_activity is already named "current_query", perhaps the
> best choice is "activity_query_size". Or "activity_query_length"?
>
> Another consideration is that it might be a good idea to name it to
> be obviously related to the controlling "track_activities" boolean.
> That would lead to "track_activity_query_size", or
> "track_activity_max_length", or some such.
>
>
>> * Minimum value of PGBE_DEFAULT_ACTIVITY_SIZE, maximum value of INT_MAX?
>>
>
> I was thinking about a range of 100 to 100K or thereabouts. INT_MAX
> is just silly...
>
>
>> I'm struggling a little to come up with a decent description of the GUC
>> variable -- something along the lines of "Sets the maximum length of
>> backend status messages". Any suggestions?
>>
>
> Be specific:
> "Sets the maximum length of pg_stat_activity.current_query."
>
>
>> Also: how should we allocate the memory for PgBackendStatus.st_activity?
>> I'm guessing it's going to be necessary to keep this in shmem ...
>>
>
> Yup. Look at existing variable-size shmem allocations.
> max_prepared_transactions might be a good reference, since it's not
> used in very many places.
>
> regards, tom lane
>
>