[Zope] Large jumps of memory use increase, and seeking overall understanding of memory use

[Jens Vagelpohl]

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On 25 Feb 2007, at 18:58, Jean Lagarde wrote:
> Memory size was at 417640 (Kb) from 03:01:40 to 03:04:41 (for three
> minutes). During these three minutes, there were requests for our
> front page and apparently everything that accompanies it in Plone,
> i.e. the Plone scripts.jss, the style sheets, bunch of icon gifs,
> image thumbs the logo.jpg, etc. No memory increase during that time.
> At 03:05:41 I logged a memory increase to 422704. Between 03:04:41 and
> 03:05:41, there was a single request at 03:05:02 for an
> image_view_fullscreen. For those unfamiliar with Plone, that is one of
> the barest page served: Just an image and a link to go back to Plone
> (none of the Plone portlets, etc.). The access log shows that the
> number of bytes returned was 1137. There was no GET for the actual
> image. There were no memory increase whatsoever for at least the next
> 30 minutes, and there were a number of other requests during that
> time. Now I'm looking for hypotheses to explain the 5Mb memory
> increase. Here are some:

Comparing the number of bytes served during a request and how much  
memory is consumed is a bit naive. You have *no* idea what all needs  
to be touched internally to serve that one object. The weightier the  
framework you run on to of Zope, the higher the chance that you're  
touching a whole lot of more or less related objects to serve the one  
you're interested in.

jens


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