Question

Installing too many plugins will slow TWiki down, is that right?

Is it possible to limit the impact by disabling the plugin (in WebPreferences?) for all but the web in which it is being used? Or is it just the fact that it's installed?

Do the same answers apply to skins?

Unless I've missed it already, it would be helpful to have these points mentioned in the standard documentation, so that new admins know whether they need to to choose and config carefully.

Environment

TWiki version:	TWikiRelease01Feb2003
TWiki plugins:	DefaultPlugin, EmptyPlugin, InterwikiPlugin
Server OS:	FreeBSD
Web server:	Apache
Perl version:	5
Client OS:	FreeBSD
Web Browser:	lynx

-- SueBlake - 01 Aug 2003

Answer

Performance impact really depends on the Plugin, some have no measurable decrease, some do. For example, the outsidePREHandler callback is expensive, or the Plugin might use many Perl libraries that needs to be initialized. At work we have a Beta installation of TWiki where we measure and document each little change to the system before/if rolling it out to the production TWiki. (Both point to the same data)

In case you need an expensive Plugin only in one web you can place the Plugin topic into that web, TWiki will initialize the Plugin only if the Plugin topic is found (which won't be the case for other webs)

TWikiPlugins is updated.

-- PeterThoeny - 01 Aug 2003

I concur with Peter. Plugins slow down TWiki even if not used, but the impact varies greatly. What I do is I measure the speed of twiki before and after a new plugin install, for instance by doing before and after:

• time wget -qO /dev/null wiki_url
• what I actually do (in bash:)
  TIMEFORMAT='%R';i=20;while let 'i>0';do time wget -qO /dev/null URL;let i=i-1;done

I have seen some plugin version adding more than 1.5s to display all pages in twiki, clearly unacceptable. For these you can either not install it, or use the above trick, or ... fix or report the performance problem of the Plugin.

Skins however incur no performance overhead, as a skin replace the standard templates by others, instead of adding things on top of the default, so for the system there is no difference between any skin and the default one. Skins can even be (marginally) faster if they use less sub-template expansion and variable expansion than the default one

-- ColasNahaboo - 01 Aug 2003

Good idea with the time wget -qO /dev/null wiki_url, I documented that in the TWikiPlugins topic.

-- PeterThoeny - 01 Aug 2003

Jeez, sometimes all ya gotta do round here is ask and wait a few minutes Thanks guys, all of that's a great help.

-- SueBlake - 01 Aug 2003