Re: too much pgbench init output - Mailing list pgsql-hackers

From Tomas Vondra
Subject Re: too much pgbench init output
Date
Msg-id 509FE111.9000007@fuzzy.cz
Whole thread Raw
In response to Re: too much pgbench init output  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: too much pgbench init output
List pgsql-hackers
On 23.10.2012 18:21, Robert Haas wrote:
> On Tue, Oct 23, 2012 at 12:02 PM, Alvaro Herrera
> <alvherre@2ndquadrant.com> wrote:
>> Tomas Vondra wrote:
>>
>>> I've been thinking about this a bit more, and do propose to use an
>>> option that determines "logging step" i.e. number of items (either
>>> directly or as a percentage) between log lines.
>>>
>>> The attached patch defines a new option "--logging-step" that accepts
>>> either integers or percents. For example if you want to print a line
>>> each 1000 lines, you can to this
>>>
>>>   $ pgbench -i -s 1000 --logging-step 1000 testdb
>>
>> I find it hard to get excited about having to specify a command line
>> argument to tweak this.  Would it work to have it emit messages
>> depending on elapsed time and log scale of tuples emitted?  So for
>> example emit the first message after 5 seconds or 100k tuples, then back
>> off until (say) 15 seconds have lapsed and 1M tuples, etc?  The idea is
>> to make it verbose enough to keep a human satisfied with what he sees,
>> but not flood the terminal with pointless updates.  (I think printing
>> the ETA might be nice as well, not sure).
>
> I like this idea.  One of the times when the more verbose output is
> really useful is when you expect it to run fast but then it turns out
> that for some reason it runs really slow.  If you make the output too
> terse, then you end up not really knowing what's going on.  Having it
> give an update at least every 5 seconds would be a nice way to give
> the user a heads-up if things aren't going as planned, without
> cluttering the normal case.

I've prepared a patch along these lines. The attached version used only
elapsed time to print the log messages each 5 seconds, so now it prints
a meessage each 5 seconds no matter what, along with an estimate of
remaining time.

I've removed the config option, although it might be useful to specify
the interval?

I'm not entirely sure how the 'log scale of tuples' should work - for
example when the time 15 seconds limit is reached, should it be reset
back to the previous step (5 seconds) to give a more detailed info, or
should it be kept at 15 seconds?

Tomas


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