Anyone know / guess why a) the limit is 20, b) the query goes awry at the limit?
Cheers, Dan. On 11 March 2011 01:16, Dan Bolser <dan.bol...@gmail.com> wrote: > Result: Recursion here isn't terrible for performance. > > Details: > > Yaron kindly set "SMWResultPrinter::$maxRecursionDepth = 40" on > http://scratchpad.referata.com and I did some testing. > > For some reason, the level of recursion now stops at level 20 (??). > I'm doing everything as before: > * http://scratchpad.referata.com/wiki/Piston > * http://scratchpad.referata.com/wiki/Template:Part_of_what > > Pages higher in the tree don't hit this limit, and the template > 'terminates' correctly, e.g. > * http://scratchpad.referata.com/wiki/Foo > > I benchmarked the performance hit due to recursion by requesting each > page in the tree 20 times using curl, and parsing out the '<!-- Served > in 0.451 secs. -->' string in the returned URL. Every page request was > done with the 'action=purge' CGI setting. > > The results are quite interesting, suggesting that each recursion adds > 0.02 seconds to the 'serve time' on scratchpad.referata.com: > * http://imagepaste.nullnetwork.net/img/1299805257test_benchmark.png > * http://oi56.tinypic.com/2gx41oy.jpg # duplicate upload > > > About the above plot, upper and lower triangles are +/- s.d. of the > mean load time (squares) in 20 trials. After depth 20 the behaviour > changes because the template doesn't deal well with this limit > condition and a large (null) results set is generated each time (see > the bottom of the 'Piston' page linked above). The 'solid' regression > includes just the points up to and including depth 20, the 'dashed' > regression includes the points above 20. > > > Cheers, > Dan. > > On 10 March 2011 13:54, Dan Bolser <dan.bol...@gmail.com> wrote: >> On 10 March 2011 12:27, Alex M. Hendler <amh.pub...@ontolawgy.com> wrote: >>> Hi Dan, >>> >>> I am not sure what "your own risk!" means, but whenever I see an >>> exclamation point in the body of a comment that is not telling you how >>> super-cool a feature is, I get a bit scared. >> >> I don't see that online here: >> http://semantic-mediawiki.org/doc/SMW__QueryPrinter_8php-source.html >> >> Perhaps it's a version issue, but in any case, I take your point. >> >> >>> That said, I can foresee a problem if you set recursion depth too high >>> and someone made an error such that a page that gets returned by the >>> query is "part of" the querying page, then you just end up with loopy >>> (literally) query results. >> >> Yeah, of course a page shouldn't be 'part of' itself, but there is >> nothing to stop a user doing that. >> >> >>> As for performance, in my experience (still yet to be confirmed by >>> others) maxRecursionDepth > 2 may cause odd property inheritance >>> behavior if you embed or transclude pages. See >>> https://bugzilla.wikimedia.org/show_bug.cgi?id=27445 >> >> Weird bug! Seems to be a 'feature' of the embed format only with nested >> queries? >> >> >>> I hope this helps point you in the right direction in terms of doing >>> what you need to do (it looks like maybe a template with known levels of >>> properties, e.g., [[-Part of::x]] passed through sufficient levels of >>> arrays/arraymaps and #if: statements would be a good bet); hopefully >> >> Yeah, I don't have a fixed number of levels. >> >> >>> someone else will be able to better answer your performance question. >>> >>> As for SemanticTreeView, it looks like it must be installed with Halo, >>> but the Ontoprise folks may have a different view of that. >> >> >> Did you get this from the docs, or have you tried installing? >> >> Thanks for your help, >> Dan. >> >>> -Alex >>> >>> >>> - >>> ----Original Message----- >>> From: Dan Bolser <dan.bol...@gmail.com> >>> To: Alex M. Hendler <amh.pub...@ontolawgy.com> >>> Cc: Semantic MediaWiki Users <semediawiki-u...@lists.sourceforge.net> >>> Subject: Re: [Semediawiki-user] Recursive ask using format=template, >>> stuck at depth of 3? >>> Date: Thu, 10 Mar 2011 10:00:32 +0000 >>> >>> Thanks Alex. >>> >>> I read the document you suggested: >>> http://semantic-mediawiki.org/doc/SMW__QueryPrinter_8php-source.html >>> >>> but I expected to see why the settings are what they are (i.e. why so >>> low), which I don't see. >>> >>> Do you think those 'odd' issues that you mention would to this simple >>> recursive query? Perhaps I'm being naive, but it seems to work so well >>> up to the given depth... would performance degrade super-linearly with >>> increased depth? >>> >>> >>> Alternatively, the Semantic TreeView extension looks promising: >>> >>> * >>> http://smwforum.ontoprise.com/smwforum/index.php/Help:Description_of_the_tree_parser_function >>> * >>> http://smwforum.ontoprise.com/smwforum/index.php/Help:Description_of_the_generateTree_parser_function >>> >>> >>> but it isn't clear from the documentation if you need to install halo >>> or not (some places state halo as a requirement, while other >>> information suggests that it isn't) ... I guess I'll just suck it and >>> see... The biggest problem is that it expects a tree while I have a >>> DAG... Not sure what that'll do to it. >>> >>> Any other suggested extensions for navigating relations? (Other than >>> Special:Browse of course!) >>> >>> >>> Cheers, >>> Dan. >>> >>> On 10 March 2011 07:39, Alex M. Hendler <amh.pub...@ontolawgy.com> wrote: >>>> Dan, >>>> >>>> I believe the setting you're looking for is >>>> >>>> SMWResultPrinter::$maxRecursionDepth = x; >>>> >>>> Place that after your enableSemantics statement in LocalSettings.php, >>>> where x = [desired depth]-1. >>>> >>>> The reason you can't get beyond 3 levels on Referata is that (I believe) >>>> it uses the default max. depth of 2. includes/SMW_QueryPrinter.php >>>> explains the recursion settings very well. >>>> >>>> The developers can correct me if I am wrong, but I believe that >>>> recursion is intentionally not more publicly documented (i.e., outside >>>> of source code) because it can do odd and perhaps unpredictable things >>>> to semantics as well as performance if you increase it above 2. >>>> >>>> You can sometimes fool the system into recursing beyond >>>> maxRecursionDepth, but that is not something I would encourage anyone to >>>> do intentionally (it also prints out very messy results). >>>> >>>> Hope this helps, >>>> Alex >>>> >>>> ----Original Message----- >>>> From: Dan Bolser <dan.bol...@gmail.com> >>>> To: Semantic MediaWiki Users <semediawiki-u...@lists.sourceforge.net> >>>> Subject: [Semediawiki-user] Recursive ask using format=template, stuck >>>> at depth of 3? >>>> Date: Wed, 9 Mar 2011 23:58:14 +0000 >>>> >>>> Hi, >>>> >>>> I wrote a nice 'recursive' template to traverse a DAG here: >>>> http://scratchpad.referata.com/wiki/Template:Part_of_what >>>> >>>> It works by calling itself with an ask using it's given input and then >>>> the result of the ask and so on up the DAG ... (recursion always makes >>>> me a little dizzy). >>>> >>>> It works great except it only calls itself a maximum of 3 times, as >>>> evidenced by comparing the results of these two pages: >>>> * http://scratchpad.referata.com/wiki/Piston >>>> * http://scratchpad.referata.com/wiki/Engine >>>> >>>> I couldn't find the appropriate setting in the manual to bump this >>>> 'maximum recursion' value. The equivalent value for MediaWiki can be >>>> found here, but note the default setting is a whopping 40: >>>> >>>> http://www.mediawiki.org/wiki/Manual:$wgMaxTemplateDepth >>>> >>>> >>>> Any tips appreciated. >>>> >>>> Cheers, >>>> Dan. >>>> >>>> ------------------------------------------------------------------------------ >>>> Colocation vs. Managed Hosting >>>> A question and answer guide to determining the best fit >>>> for your organization - today and in the future. >>>> http://p.sf.net/sfu/internap-sfd2d >>>> _______________________________________________ >>>> Semediawiki-user mailing list >>>> semediawiki-u...@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/semediawiki-user >>>> >>>> >>> >>> >> > > ------------------------------------------------------------------------------ > Colocation vs. Managed Hosting > A question and answer guide to determining the best fit > for your organization - today and in the future. > http://p.sf.net/sfu/internap-sfd2d > _______________________________________________ > Semediawiki-user mailing list > semediawiki-u...@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/semediawiki-user > ------------------------------------------------------------------------------ Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d _______________________________________________ Semediawiki-devel mailing list Semediawiki-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/semediawiki-devel
