distributedINFORMATION.com

And along the way, TWiki’s inbuilt Topic and structured Search is going to get a boost too.

I’ve been working on trying to bring SearchEngineKinoSearchAddOn into TWiki properly - by adding it as a configuration item in the SearchAlgorithms. So far, its a pretty cool - it super fast, especially on my test topic set of 50,000 plants - even allowing simple structured queries based on TWiki FormFields.

The work will require a few refactorings that will be in TWiki 4.2.2 and above (planned for mid-September), so I expect things to move along quickly.

This release makes over 150 improvements to the current Enterprise TWiki.

Along with many WYSIWYG Editing improvements, better UTF8 support, User mapping fixes and SEARCH improvements, This release contains an optimization that should see 4.2.1 being 10-30% faster than 4.2.0.

I will be updating the TWikiInstallers as soon as I can - the Windows installer should see the biggest impact, as I have managed to fix a number of SEARCH issues that are windows specific.

see TWikiRelease04×02x01 for more details.

(test post using Gnome Webog poster)

The last fortnight, I’ve been working on creating a new, soon to be released to web 2.0 ‘Beta’ site based on TWiki 4.2.0. That means that I’ve been busy finding, reporting and fixing Bugs for TWiki 4.2.1.

The list todate are:

Item5455 BuildContrib doesn’t cope with larger numbers of files Closed 15 Apr 2008 - 04:34 SvenDowideit

Item5536 robots.txt is missing some obvious scripts - like login Waiting for Release 14 Apr 2008 - 08:43 SvenDowideit

Item5535 IF{”$BANNER” does not really work. Waiting for Release 14 Apr 2008 - 06:49 SvenDowideit

Item5534 missing contexts for several bin scripts Waiting for Release 14 Apr 2008 - 06:25 SvenDowideit

Item5533 tmpl login script does not do writeCompletePage, so it does not get addToHEAD bits. Waiting for Release 14 Apr 2008 - 05:10 SvenDowideit

Item5513 update TalkContrib topic Closed 11 Apr 2008 - 06:19 SvenDowideit

Item5509 IF & query String matching may be incorrectly greedy. Waiting for Release 11 Apr 2008 - 01:55 SvenDowideit

Item5501 IF allows does not work correctly if the topic does not exist. Waiting for Release 11 Apr 2008 - 01:41 SvenDowideit

Item5510 initial version of TalkContrib Closed 09 Apr 2008 - 08:11 SvenDowideit

Item5499 TWiki::UI::Resister::changePassword sends login, not cUID to TWiki::Users::setPassword Waiting for Release 04 Apr 2008 - 02:24 SvenDowideit

Item5496 Conclusion: Turn off UTF-8 test case until bug is fixed (4.2 branch only) Waiting for Release 03 Apr 2008 - 02:06 SvenDowideit

Item5495 add twikiBroadcastMessage class div to default & classic skins Waiting for Release 03 Apr 2008 - 00:53 SvenDowideit

I’ve ported my additional DTrace probes to blead perl, adding the following probes

• new-sv and del-sv to track Perl allocations,
• main-enter and main-exit to show what part of Perl’s execution phase we’re in
• load-module-entry and load-module-return to instrument use, require, do.

I’ve also started to document the probes at http://wikis.sun.com/display/DTrace/perl+Provider
To use the patch,

1. get bleadperl:
   1. rsync -avz –exclude .svn/ –delete rsync://ftp.linux.activestate.com/perl-current/ bleadperl
2. apply the patch:
3. cd bleadperl ; patch ../bleadperl.diff
4. run configure with dtrace enabled:
   1. ./Configure -de -Dusedevel -Dinc_version_list=none -Dprefix=/usr/local/bleadperl/ -Dldflags=-Dman3ext=3pm -Duseithreads -Duseshrplib -Uversiononly -Dusedtrace -Doptimize=-g
5. make
6. make test
7. make install
8. run./perl.d (also found at http://distributedinformation.com/DTrace/ ) and then run whatever Perl code you want to instrument.

Given the following functionally similar Perl modules, I was curious what the internal Perl differences in execution were.

To recap - (from PerlDoc)

• Perl use - Imports some semantics into the current package from the named module - It is exactly equivalent to

      BEGIN { require Module; Module->import( LIST ); }

• Perl require - demands that a library file be included if it hasn’t already been included. There is pseudocode there to suggest that a previously required module (successful or not) would just return the previous result

So given a set of modules that don’t define an import() function, one would expect that there would be little difference.

The (1/0) tuples in braces are counts of allocations and deallocations by the Perl interpreter in in that enter-return pair, and execution times are all using DTrace’s vtimestamp, so are adjusted for time on CPU.

This suggests to me that Perl use and require suffer from the same problems that are encountered when using #include’s inside header files in large scale C and C++, a massive, un-realized parser mess, due to the re-importation of dependencies for the short term convenience of the developer.

While the require output appears better, none the less (looking at the source code for Perl_ck_require) it does more than a nop the second time around (at minimum, its doing a single allocation, and converting the Module name to a File.pm). It is interesting (scary really) that the use case has many more allocations than the require case, but I presume that has to do with the sillyness of importing code into the same namespace several times. That main.pl’s BEGIN is parsed&allocated for 9 times, and Module2:BEGIN is parsed&allocated for twice - is not really what I had in mind.

For those of us working with large scale Perl code (in my case TWiki and Catalyst) it seems that there is not enough clarity, and there are opposing concerns for users that run Perl directly, incurring the parse and allocate steps each time, and those using accelerators such as mod_perl and speedy_cgi, who essentially start at the main-run phase (I think).

Reducing the above examples by removing the use or requires from everywhere except the top level main.pl, still shows an unexpected side effect that the use case has 34 more allocations and 26 deallocations - but… there is less going on. So it is possible, that the inconvenience of needing to manage the Perl module loading at the top level might be worth while, at least until Perl is changed to do what the ‘manual’ implies.

Another interesting side effect of replacing use with require, is that it moves the execution of the BEGIN from the parse phase to the execution phase - again reducing the effectiveness of Perl accelerators, but perhaps more inline with simplistic expectations.

Seems to me its time to move to bleadperl, and see if I can offer a fix.

The above tests are done using the dtrace enabled Perl 5.8.8 that is in my svn repository.

I have just uploaded the OpenIDUserContrib for TWiki 4.2.0. It adds OpenID login and 1.1 Attribute functionalty to TWiki.

Currently, it disables Registration, and limits authentication to OpenID users.

It has the advantage over the OpenIDAuth apache module, that it automatically requests the User’s OpenId 1.1 attributes like Name, Email address directly from their OpenID identity.

While it trusts the user’s choice of ‘FullName’ registration attribute when displaying who made changes to topics, the TWiki topic source
actually stores the authenticating OpenID URI, thus their user details will be updated from the authentication server next time they log in.

Note that TWiki Topic based Groups are not yet implemented using this Mapper.

Future directions

• add mixing of UserMappers to allow OpenID and ‘normal’ TWiki auth
• turn TWiki into an OpenID identity server
• add Safe Group definition system
• add OpenId to TWiki’s registration process (would require openid auth first, then prefill registration details from any available attributes
  • This will require re-writing of TWiki’s inbuilt registration system
• move the list of Known users and their mapping information from data/OpenIdUsers.txt to somewhere more scalable. (perhaps DBI)
  • combine the info TWiki uses persistently with the Session and other caching info OpenID11? uses

Net::OpenID11 (based on Net::JanRain::OpenID)

To make this work, I fixed the Perl bugs I found in Net::JanRain::OpenID, and renamed the resulting modules under Net::openID11 (as it is not OpenID2.0). I expect to upload these packages to CPAN some time soon.

If you want to take a look at the code - goto my Subversion repository