[Mongrel] deciphering objects.log

Evan Weaver evan at cloudbur.st
Fri Oct 12 23:52:24 EDT 2007

Bleakhouse isn't as detailed as it could be, but it's better than
using Objectspace.

Zed, do you think we should remove the object.log? My guess is that it
leads people astray as much as it helps.

Ara Howard has some good ideas in his leak checker "Dike", but again,
it uses Objectspace.


On 10/12/07, Zed A. Shaw <zedshaw at zedshaw.com> wrote:
> On Fri, 12 Oct 2007 11:39:20 -0700
> Carlos <carlos at bueno.org> wrote:
> > I RTFCd and got this:
> >
> >     $objects_out.puts "run,classname,last,count,delta,lenmean,lensd,lenmax"
> >
> > So,
> > run: a serial number of the request
> > classname: obvious
> > last: number of object from previous run
> > count: number of objects in this run
> > delta: last - count
> > lenmean: average length of object
> > lensd: std deviation
> > lenmax: largest-seen (or maybe largest-existing?) object of this class
> >
> > Right?
> Yep, except len(mean|sd|max) are used for objects that report a length, and that header should be created if the file is first created.  You must have truncated it at some point.
> How you use this file is you run a *sequential* number of hits and do it in *production* mode.  When it's done you load it into a spreadsheet or R or some Ruby and you look for the following:
> 1) Any class which seems to have a count who's delta mean isn't close to 0 for all runs.  A leak can actually be defined in a GC language as: any class who's object count delta over time do not have a mean of 0.
> 2) Any class who's average length or sd.dev length is gigantic (send_file anyone?).
> 3) Any classes who have a mean of 0, but have a sd.dev that's massive.  This shows poor GC management since it's a huge number of object being created and destroyed.
> 4) Any other column that for any class seems to be not like the others.
> Also look at bleakhouse.
> --
> Zed A. Shaw
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Evan Weaver
Cloudburst, LLC

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