Merge commit 'schmonz/master'

[git.ikiwiki.info.git] / doc / todo / should_optimise_pagespecs.mdwn

diff --git a/doc/todo/should_optimise_pagespecs.mdwn b/doc/todo/should_optimise_pagespecs.mdwn
index f3048f3281e285175b44037072d82d92c677d509..728ab89943488e0656b13c7c2947b0d379a3475d 100644 (file)
--- a/doc/todo/should_optimise_pagespecs.mdwn
+++ b/doc/todo/should_optimise_pagespecs.mdwn
@@ -79,8 +79,6 @@ I can think about reducung the size of my wiki source and making it available on
 > 
 > --[[Joey]]
 
 > 
 > --[[Joey]]
 

-[[!template id=gitbranch branch=smcv/ready/optimize-depends author="[[smcv]]"]]
-

 >> I've been looking at optimizing ikiwiki for a site using
 >> [[plugins/contrib/album]] (which produces a lot of pages) and it seems
 >> that checking which pages depend on which pages does take a significant
 >> I've been looking at optimizing ikiwiki for a site using
 >> [[plugins/contrib/album]] (which produces a lot of pages) and it seems
 >> that checking which pages depend on which pages does take a significant


@@ -90,6 +88,8 @@ I can think about reducung the size of my wiki source and making it available on
 >> rather than a single pagespec. This does turn out to be faster, although
 >> not as much as I'd like. --[[smcv]]
 
 >> rather than a single pagespec. This does turn out to be faster, although
 >> not as much as I'd like. --[[smcv]]
 

+>>> [[Merged|done]] --[[smcv]]
+

 >>> I just wanted to note that there is a whole long discussion of dependencies and pagespecs on the [[todo/tracking_bugs_with_dependencies]] page. -- [[Will]]
 
 >>>> Yeah, I had a look at that (as the only other mention of `pagespec_merge`).
 >>> I just wanted to note that there is a whole long discussion of dependencies and pagespecs on the [[todo/tracking_bugs_with_dependencies]] page. -- [[Will]]
 
 >>>> Yeah, I had a look at that (as the only other mention of `pagespec_merge`).


@@ -98,8 +98,6 @@ I can think about reducung the size of my wiki source and making it available on
 >>>> I haven't actually deleted it), because the "or" operation is now done in
 >>>> the Perl code, rather than by merging pagespecs and translating. --[[smcv]]
 
 >>>> I haven't actually deleted it), because the "or" operation is now done in
 >>>> the Perl code, rather than by merging pagespecs and translating. --[[smcv]]
 

-[[!template id=gitbranch branch=smcv/ready/remove-pagespec-merge author="[[smcv]]"]]
-

 >>>>> I've now added a patch to the end of that branch that deletes
 >>>>> `pagespec_merge` almost entirely (we do need to keep a copy around, in
 >>>>> ikiwiki-transition, but that copy doesn't have to be optimal or support
 >>>>> I've now added a patch to the end of that branch that deletes
 >>>>> `pagespec_merge` almost entirely (we do need to keep a copy around, in
 >>>>> ikiwiki-transition, but that copy doesn't have to be optimal or support


@@ -244,11 +242,13 @@ more complicated every time!
 >    other things that overloaded the system.
 > b) Suggests to me we will probably want to force a rebuild on upgrade
 >    when fixing this (via the mechanism in the postinst).
 >    other things that overloaded the system.
 > b) Suggests to me we will probably want to force a rebuild on upgrade
 >    when fixing this (via the mechanism in the postinst).

-> 
-> BTW, the underlying bug here is really horribly simple:
-> When refreshing, `loadindex` preserves the previous depends list,
-> and `add_depends` adds stuff to it. So it doubles every time a page is
-> re-rendered during refresh. --[[Joey]]
+>
+> I've investigated why the pagespecs keep growing: When page A changes,
+> its old depends are cleared. Then
+> page B that inlines A gets rebuilt, and its old depends are also cleared.
+> But page B also inlines page C; which means C gets re-rendered. And this
+> happens w/o its old depends being cleared, so C's depends are doubled.
+> --[[Joey]]

 
 After the initial optimization: 14.27s to rebuild, 8.26/8.33/8.26 to refresh.
 Success!
 
 After the initial optimization: 14.27s to rebuild, 8.26/8.33/8.26 to refresh.
 Success!


@@ -262,6 +262,9 @@ might well be experimental error, for that matter).
 > `add_depends` had no effect. So, the commit message to
 > b6fcb1cb0ef27e5a63184440675d465fad652acf is actually wrong.. ? --[[Joey]] 
 
 > `add_depends` had no effect. So, the commit message to
 > b6fcb1cb0ef27e5a63184440675d465fad652acf is actually wrong.. ? --[[Joey]] 
 

+>> I'll try benchmarking again on the non-public wiki where I had the 4%
+>> speedup. The docwiki is so small that 4% is hard to measure... --[[smcv]]
+

 Not saving {depends} to the index, using a hash instead of a list to
 de-duplicate, and allowing add_depends to take an arrayref instead of a single
 pagespec had no noticable positive or negative effect on this test.
 Not saving {depends} to the index, using a hash instead of a list to
 de-duplicate, and allowing add_depends to take an arrayref instead of a single
 pagespec had no noticable positive or negative effect on this test.


@@ -269,11 +272,17 @@ pagespec had no noticable positive or negative effect on this test.
 > I see e4cd168ebedd95585290c97ff42234344bfed46c is still in your branch
 > though. I don't like using an arrayref, it could just take `($page, @depends)`.
 > and I don't see the need to keep it if it doesn't currently help.
 > I see e4cd168ebedd95585290c97ff42234344bfed46c is still in your branch
 > though. I don't like using an arrayref, it could just take `($page, @depends)`.
 > and I don't see the need to keep it if it doesn't currently help.

-> 
+
+>> I'll drop it. --[[smcv]]
+

 > Is there any reason to keep 7227c2debfeef94b35f7d81f42900aa01820caa3
 > if it doesn't improve speed?
 > --[[Joey]] 
 
 > Is there any reason to keep 7227c2debfeef94b35f7d81f42900aa01820caa3
 > if it doesn't improve speed?
 > --[[Joey]] 
 

+>> I'll try benchmarking on a more complex wiki and see whether it has a
+>> positive or negative effect. It does avoid being O(n**2) in number of
+>> dependencies. --[[smcv]]
+

 Memoizing the results of pagename brought the rebuild time down to 14.06s
 and the refresh time down to 7.96/7.92/7.92, a significant win.
 
 Memoizing the results of pagename brought the rebuild time down to 14.06s
 and the refresh time down to 7.96/7.92/7.92, a significant win.
 


@@ -281,6 +290,9 @@ and the refresh time down to 7.96/7.92/7.92, a significant win.
 > called with a great many inputs.) Why did you chose to memoize it
 > explicitly rather than adding it to the memoize list at the top?
 
 > called with a great many inputs.) Why did you chose to memoize it
 > explicitly rather than adding it to the memoize list at the top?
 

+>> It does depend on global variables, so using Memoize seemed like asking for
+>> trouble. I suppose what I did is equivalent to Memoize though... --[[smcv]]
+

 Refactoring to use pagespec_match_list looks more risky from a code churn
 point of view; rebuild now takes 14.35s, but refresh is only 7.30/7.29/7.28,
 another significant win.
 Refactoring to use pagespec_match_list looks more risky from a code churn
 point of view; rebuild now takes 14.35s, but refresh is only 7.30/7.29/7.28,
 another significant win.