Re: too much pgbench init output

On Sun, Dec 9, 2012 at 8:11 AM, Tomas Vondra <tv(at)fuzzy(dot)cz> wrote:

> On 20.11.2012 08:22, Jeevan Chalke wrote:
> > Hi,
> >
> >
> > On Tue, Nov 20, 2012 at 12:08 AM, Tomas Vondra <tv(at)fuzzy(dot)cz
> > <mailto:tv(at)fuzzy(dot)cz>> wrote:
> >
> > On 19.11.2012 11:59, Jeevan Chalke wrote:
> > > Hi,
> > >
> > > I gone through the discussion for this patch and here is my review:
> > >
> > > The main aim of this patch is to reduce the number of log lines.
> It is
> > > also suggested to use an options to provide the interval but few
> of us
> > > are not much agree on it. So final discussion ended at keeping 5
> sec
> > > interval between each log line.
> > >
> > > However, I see, there are two types of users here:
> > > 1. Who likes these log lines, so that they can troubleshoot some
> > > slowness and all
> > > 2. Who do not like these log lines.
> >
> > Who likes these lines / needs them for something useful?
> >
> >
> > No idea. I fall in second category.
> >
> > But from the discussion, I believe some people may need detailed (or lot
> > more) output.
>
> I've read the thread again and my impression is that no one really needs
> or likes those lines, but
>
> (1) it's rather pointless to print a message every 100k rows, as it
> usually fills the console with garbabe
>
> (2) it's handy to have regular updates of the progress
>
> I don't think there're people (in the thread) that require to keep the
> current amount of log messages.
>
> But there might be users who actually use the current logs to do
> something (although I can't imagine what). If we want to do this in a
> backwards compatible way, we should probably use a new option (e.g.
> "-q") to enable the new (less verbose) logging.
>
> Do we want to allow both types of logging, or shall we keep only the new
> one? If both, which one should be the default one?
>

Both the options are fine with me, but the default should be the current
behaviour.

> > > So keeping these in mind, I rather go for an option which will
> control
> > > this. People falling in category one can set this option to very
> low
> > > where as users falling under second category can keep it high.
> >
> > So what option(s) would you expect? Something that tunes the interval
> > length or something else?
> >
> >
> > Interval length.
>
> Well, I can surely imagine something like "--interval N".
>

+1

>
> > A switch that'd choose between the old and new behavior might be a
> good
> > idea, but I'd strongly vote against "automagic" heuristics. It makes
> the
> > behavior very difficult to predict and I really don't want to force
> the
> > users to wonder whether the long delay is due to general slowness of
> the
> > machine or some "clever" logic that causes long delays between log
> > messages.
> >
> > That's why I choose a very simple approach with constant time
> interval.
> > It does what I was aiming for (less logs) and it's easy to predict.
> > Sure, we could choose different interval (or make it an option).
> >
> >
> > I am preferring an option for choosing an interval, say from 1 second to
> > 10 seconds.
>
> Ummmm, why not to allow arbitrary integer? Why saying 1 to 10 seconds?
>

Hmm.. actually, I have no issues with any number there. Just put 1..10 as
we hard-coded it 5. No particular reason as such.

>
> > BTW, what if, we put one log message every 10% (or 5%) with time taken
> > (time taken for last 10% (or 5%) and cumulative) over 5 seconds ?
> > This will have only 10 (or 20) lines per pgbench initialisation.
> > And since we are showing time taken for each block, if any slowness
> > happens, one can easily find a block by looking at the timings and
> > troubleshoot it.
> > Though 10% or 5% is again a debatable number, but keeping it constant
> > will eliminate the requirement of an option.
>
> That's what I originally proposed in September (see the messages from
> 17/9), and Alvaro was not relly excited about this.
>
> Attached is a patch with fixed whitespace / indentation errors etc.
> Otherwise it's the same as the previous version.
>

OK. Looks good now.

Any other views / suggestions are welcome.

Thanks

> Tomas
>
>
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--
Jeevan B Chalke
Senior Software Engineer, R&D
EnterpriseDB Corporation
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