Re: proposal: add 'waiting for replication' to pg_stat_activity.state

On Thu, Dec 3, 2015 at 9:02 AM, Craig Ringer <craig(at)2ndquadrant(dot)com> wrote:
>
> On 3 December 2015 at 09:32, Peter Eisentraut <peter_e(at)gmx(dot)net> wrote:
>>
>> On 12/2/15 7:00 PM, Craig Ringer wrote:
>> > I notice that you don't set the 'waiting' flag. 'waiting' is presently
>> > documented as:
>> >
>> > <entry>True if this backend is currently waiting on a
lock</entry>
>> >
>> > ... but I'm inclined to just widen its definition and set it here,
since
>> > we most certainly are waiting, and the column isn't named
>> > 'waiting_on_a_lock'. It shouldn't upset various canned lock monitoring
>> > queries people have since they generally do an inner join on pg_locks
>> > anyway.
>>
>> I'm not so sure about that assumption.
>
>
> Even if it's an outer join, the worst that'll happen is that they'll get
entries with nulls in pg_locks. I don't think it's worth worrying about too
much.
>

That can be one way of dealing with it and another is that we
keep the current column as it is and add another view related
wait stats, anyway we need something like that for other purposes
like lwlock waits etc. Basically something on lines what we
is being discussed in thread [1]

[1] -
http://www.postgresql.org/message-id/CAA4eK1+=5Ex8-5NRr3u94=_t2p65v0kcjZ5rXddVmkx=LwAJ+w@mail.gmail.com

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com