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From Philippe <watche...@gmail.com>
Subject Re: Meaning of values in tpstats
Date Sun, 11 Dec 2011 09:54:39 GMT
Was't that on the 1.0 branch ? I'm still running 0.8x ?

@Peter: investigating a little more before answering. Thanks

2011/12/10 Edward Capriolo <edlinuxguru@gmail.com>

> There was a recent patch that fixed an issue where counters were hitting
> the same natural endpoint rather then being randomized across all of them.
>
>
> On Saturday, December 10, 2011, Peter Schuller <
> peter.schuller@infidyne.com> wrote:
> >> Pool Name                    Active   Pending      Completed   Blocked
>  All
> >> time blocked
> >> ReadStage                        27      2166     3565927301         0
> >
> > In general, "active" refers to work that is being executed right now,
> > "pending" refers to work that is waiting to be executed (go into
> > "active"), and completed is the cumulative all-time (since node start)
> > count of the number of tasks executed.
> >
> > With the slicing, I'm not sure off the top of my head. I'm sure
> > someone else can chime in. For e.g. a multi-get, they end up as
> > independent tasks.
> >
> > Typically having pending persistently above 0 for ReadStage or
> > MutationStage, especially if more than a hand-ful, means that you are
> > having a performance issue - either capacity problem or something
> > else, as incoming requests will have to wait to be services. Typically
> > the most common effect is that you are bottlenecking on I/O and
> > ReadStage pending shoots through the roof.
> >
> > There are exceptions. If you e.g. submit a really large multi-get of
> > 5000, that will naturally lead to a spike (and if all 5000 of them
> > need to go down to disk, the spike will survive for a bit). If you are
> > ONLY doing these queries, that's not a problem per se. But if you are
> > also expecting other requests to have low latency, then you want to
> > avoid it.
> >
> > In general, batching is good - but don't overdo it, especially for
> > reads, and especially if you're going to disk for the workload.
> >
> > --
> > / Peter Schuller (@scode, http://worldmodscode.wordpress.com)
> >
>

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