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I'm still trying to optimize ikiwiki for a site using [[plugins/contrib/album]], and checking which pages depend on which pages is still taking too long. Here's another go at fixing that, using [[Will]]'s suggestion from [[todo/should_optimise_pagespecs]]:

A hash, by itself, is not optimal because the dependency list holds two things: page names and page specs. The hash would work well for the page names, but you'll still need to iterate through the page specs. I was thinking of keeping a list and a hash. You use the list for pagespecs and the hash for individual page names. To make this work you need to adjust the API so it knows which you're adding. -- [[Will]]

If you have P pages and refresh after changing C of them, where an average page has E dependencies on exact page names and D other dependencies, this branch should drop the complexity of checking dependencies from O(P * (D+E) * C) to O(C + PE + PD*C). Pages that use inline or map have a large value for E (e.g. one per inlined page) and a small value for D (e.g. one per inline).

Benchmarking:

Test 1: a wiki with about 3500 pages and 3500 photos, and a change that touches about 350 pages and 350 photos

Test 2: the docwiki (about 700 objects not excluded by docwiki.setup, mostly pages), docwiki.setup modified to turn off verbose, and a change that touches the 98 pages of plugins/*.mdwn

In both tests I rebuilt the wiki with the target ikiwiki version, then touched the appropriate pages and refreshed.

Results of test 1: without this branch it took around 5:45 to rebuild and around 5:45 again to refresh (so rebuilding 10% of the pages, then deciding that most of the remaining 90% didn't need to change, took about as long as rebuilding everything). With this branch it took 5:47 to rebuild and 1:16 to refresh.

Results of test 2: rebuilding took 14.11s without, 13.96s with; refreshing three times took 7.29/7.40/7.37s without, 6.62/6.56/6.63s with.

(This benchmarking was actually done with my [[plugins/contrib/album]] branch, since that's what the huge wiki needs; that branch doesn't alter core code beyond the ready/depends-exact branch point, so the results should be equally valid.)

--[[smcv]]

Now [[merged|done]] --[[smcv]]


We discussed this on irc; I had some worries that things may have been switched to add_depends_exact that were not pure page names. My current feeling is it's all safe, but who knows. It's easy to miss something. Which makes me think this is not a good interface.

Why not, instead, make add_depends smart. If it's passed something that is clearly a raw page name, it can add it to the exact depends hash. Else, add it to the pagespec hash. You can tell if it's a pure page name by matching on $config{wiki_file_regexp}.

Good thinking. Done in commit 68ce514a 'Auto-detect "simple dependencies"', with a related bugfix in e8b43825 "Force %depends_exact to lower case".

Performance impact: Test 2 above takes 0.2s longer to rebuild (probably from all the calls to lc, which are, however, necessary for correctness) and has indistinguishable performance for a refresh.

Test 1 took about 6 minutes to rebuild and 1:25 to refresh; those are pessimistic figures, since I've added 90 more photos and 90 more pages (both to the wiki as a whole, and the number touched before refreshing) since testing the previous version of this branch. --[[smcv]]

Also I think there may be little optimisation value left in 7227c2debfeef94b35f7d81f42900aa01820caa3, since the "regular" dependency lists will be much shorter.

You're probably right, but IMO it's not worth reverting it - a set (hash with dummy values) is still the right data structure. --[[smcv]]

Sounds like inline pagenames has an already exstant bug WRT pages moving, which this should not make worse. Would be good to verify.

If you mean the standard "add a better match for a link-like construct" bug that also affects sidebar, then yes, it does have the bug, but I'm pretty sure this branch doesn't make it any worse. I could solve this at the cost of making pagenames less useful for interactive use, by making it not respect [[ikiwiki/subpage/LinkingRules]], but instead always interpret its paths as relative to the top of the wiki - that's actually all that [[plugins/contrib/album]] needs. --[[smcv]]

Re coding, it would be nice if refresh() could avoid duplicating the debug message, etc in the two cases. --[[Joey]]

Fixed in commit f805d566 "Avoid duplicating debug message..." --[[smcv]]