Обсуждение: where is pg_stat_activity (and others) in the documentation?

Hi,

I can't find pg_stat_activity in the the documentation.
There are many pg_stat_xxx tables and views, but their columns are not described, or so it seems.
Maybe that is a bug in the documentation, then.

I was looking for what exactly "waiting" means in pg_stat_activity. In the 9.0.1 documentation, it is mentioned that it shows the "waiting status" but that doesn't really help.
http://www.postgresql.org/docs/current/static/monitoring-stats.html#MONITORING-STATS-VIEWS

I was looking for the answer for postgresql version 8.3 (it might differ).

Cheers,

Willy-Bas Loos

--
"Patriotism is the conviction that your country is superior to all others because you were born in it." -- George Bernard Shaw

On Mon, Nov 15, 2010 at 5:15 AM, Willy-Bas Loos <willybas@gmail.com> wrote:
> I was looking for what exactly "waiting" means in pg_stat_activity.

waiting for a lock.

--
"Patriotism is the conviction that your country is superior to all others because you were born in it." -- George Bernard Shaw

>> You can find out exactly what you're waiting for by correlating this to
>> the
>> pg_locks table.
>>   Grab the 'procpid' of your waiting query and run:
>>   select * from pg_locks where pid=<thepid> and granted='f';
>>   Notice, in the pg_locks table, the logic works slightly different...
>> if
>> you're 'waiting' (pg_stat_activity), then you haven't been 'granted'
>> (pg_locks).
>>
> Thanks.
>
>
>> As far as documentation:
>> http://www.postgresql.org/docs/current/static/monitoring-stats.html
>>
> I do think that we need per-column documentation of the Standard
> Statistics
> Views.
> Would it be considered for the documentation if i give describing them a
> try?

What's wrong with these docs?
http://www.postgresql.org/docs/9/static/catalogs.html

And when it comes to statistics views (pg_stat/pg_statio), don't forget
most of the columns correspond to a function - just display the view
definition and search for documentation for each function separately.

It'd be nice to have the documentation for each view too, not for each
function only, but on the other hand that would be redundancy.

Tomas

tv@fuzzy.cz writes:
>> I do think that we need per-column documentation of the Standard
>> Statistics Views.

> What's wrong with these docs?
> http://www.postgresql.org/docs/9/static/catalogs.html

Or, more to the point, these docs:
http://developer.postgresql.org/pgdocs/postgres/monitoring-stats.html#MONITORING-STATS-VIEWS

            regards, tom lane

Dne 17.11.2010 16:22, Tom Lane napsal(a):
> tv@fuzzy.cz writes:
>>> I do think that we need per-column documentation of the Standard
>>> Statistics Views.
>
>> What's wrong with these docs?
>> http://www.postgresql.org/docs/9/static/catalogs.html
>
> Or, more to the point, these docs:
> http://developer.postgresql.org/pgdocs/postgres/monitoring-stats.html#MONITORING-STATS-VIEWS

Yes, but that's just the general description of the views, including a
brief description of the columns. But sometimes it's difficult to see
which column is actually described and the description available for the
function is usually bit more detailed.

For example pg_stat_bgwriter view is described like this (quoting just
part of the description):

    One row only, showing cluster-wide statistics from the background
    writer: number of scheduled checkpoints, requested checkpoints, ...

That's a fair amount of information, but if you do

    \d+ pg_stat_bgwriter

you'll immediately see that checkpoints_timed corresponds to a call to
pg_stat_get_bgwriter_timed_checkpoints, and this is described like this

    Number of times the background writer has started timed checkpoints
    (because the checkpoint_timeout time has expired)

Which is a bit more detailed that the description of the view.

regards
Tomas

What i think we need is something like this
http://www.postgresql.org/docs/9/static/catalogs.html
for the pg_stat* views

Cheers, have a nice day,

WBL

--
"Patriotism is the conviction that your country is superior to all others because you were born in it." -- George Bernard Shaw