[Zope-CMF] Re: [dev] listFilteredActionsFor performance

[Tres Seaver]

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yuppie wrote:
> Hi!
> 
> 
> Recently there was some discussion about listFilteredActionsFor
> performance:
> http://mail.zope.org/pipermail/zope-cmf/2005-April/022110.html
> 
> and I noticed Tres was experimenting with some CMF 1.5 modifications:
> http://mail.zope.org/pipermail/cmf-checkins/2005-April/006014.html
> http://mail.zope.org/pipermail/cmf-checkins/2005-April/006015.html
> 
> 
> These are my observations:
> 
> The time spent in listFilteredActionsFor heavily depends on the specific
> usage of Actions:
> 
> - number and kind of Action providers
> - number of Actions
> - number of expressions
> - number of workflow definitions
> - anonymous or authenticated users
> - size of the site
> 
> So it's hard to measure performance. But in general most time is spent
> in expressions and in the WorkflowTool. Within the WorkflowTool,
> worklists are by far the most expensive Actions.

... because they involve catalog queries.  We could perhaps optimize
that query via a dedicated TopicIndex for the 'review_state' portion.

> Can anybody confirm these observations?
> 
> @Tres: Do you have different results? Were you able to improve the
> performance significantly?

Most of my hackery was aimed at two potential hotspots:

  - The MembershipTool has ridiculously expensive expressions for its
    actions.  I added two new top-level names to the Expression
    namespace, 'member_folder' and 'member_url', which made the
    expressions both cheaper (the bypass some redundant security
    checking) and simpler (therefore cheaper as well).

  - The action providers all manufacture their own expression contexts,
    which might be a hotspot.

I didn't get a chance to measure enough the speedups (or slowdowns ;).
I expect that looking at the other expressions would be valuable, as
well (e.g., removing the syndication tool as a provider on sites which
don't allow syndication anywhere).

Tres.
- --
===============================================================
Tres Seaver                                tseaver at zope.com
Zope Corporation      "Zope Dealers"       http://www.zope.com
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