[pmwiki-users] Pageindex and distributed documentation (Was Strange pagelist behaviour)

Marc Cooper gmane at auxbuss.com
Fri Jun 16 12:52:51 CDT 2006


Patrick R. Michaud said...
> On Tue, Jun 13, 2006 at 09:43:56AM -0400, Pico wrote:
> > In a thread called "Strange pagelist behavior" Marc Cooper wrote:
> > > Anyway, the long and short of it is that I deleted the .pageindex file 
> > > in the home wiki, and missing items reappeared.
> 
> Oops.  Yes, this is a "bug", but it's a bug allowed by
> design for performance reasons.  I just haven't been very good
> about pointing out the places where the bug manifests itself,
> and you stumbled across one.  Mea culpa.

:-) I would just like to blow a big raspberry at Pico at this point :-P
 
> > (1) Are there situations when we should recommend that administrators 
> > delete their pageindex file as part of an upgrade?
> 
> Probably.  Better still would be for PmWiki to automatically detect
> when it's a good idea to rebuild the .pageindex file from scratch,
> but until we get to that point I should probably be more careful
> about .pageindex.

Just a comment, but dokuwiki provides a rebuild utility for its 
searchindex (i.e. indexer.php).

My personal opinion is to avoid anything that slows down pmwiki - not 
suggesting you would, etc. I'd far rather have an option to run a check 
on .pageindex, and then rebuild, if necessary, as part of my admin 
routine.

> Background:  .pageindex is a file that helps improve the performance
> of searches and pagelists by reducing the number of pages that have
> to be scanned to produce results.  When PmWiki is first installed,
> .pageindex doesn't exist, but PmWiki slowly builds the index in
> response to search requests and page edits.  Eventually the entire
> index is built and things run reasonably fast.
> 
> As long as pages change due to normal edits, everything is okay,
> but if a page's contents change via some external mechanism, such
> a performing an update, then the .pageindex can be "out of sync"
> with its contents.  That's what appears to have happened here

Yes.

> > (2) Are there other situations, besides pageindex, where upgrades to 
> > wikifarms may involve issues that might not ordinarily be a concern when 
> > upgrading to a non-farm installation?
> 
> I'm sure there are but I can't think of any at the moment.  
> And this particular case wasn't unique to farms -- any upgrade
> to a simple wiki site can cause the .pageindex to be out of
> date for any distributed pages that may have changed.

Yes, the problem I had was in the home wiki, the farm wiki was fine, and 
that's how I identified the problem. If I hadn't added the farm, then I 
wouldn't have discovered the home wiki was at fault. That's actually why 
I mentioned the problem, in case other folk had the problem, but didn't 
know.

Would you recommend deleting all .pageindex files after an update, for 
now?

-- 
Best,
Marc





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