I’m sorry.. this is N^2 because the Timer just keeps growing for every new queue and they need to be purged and it has to evaluate each one.
On Sat, May 2, 2015 at 1:40 PM, Kevin Burton <bur...@spinn3r.com> wrote: > Also, while this is a small performance boost in my example, this should > have a massive impact when running with large queues. It’s calling > Timer.purge() on each queue GC and if you have a lot of queues you’re going > to have a lot of TimerTasks so this is a O(N). It also holds a global lock > during this operation so no new queues can be created during a queue GC. > > On Sat, May 2, 2015 at 12:23 PM, Kevin Burton <bur...@spinn3r.com> wrote: > >> I’m doing a bunch of performance analysis of ActiveMQ this weekend to see >> if I can improve queue creation and destruction time. The good news is >> that there are a lot of areas of optimization. >> >> It looks like one is that advisory topics are created with the default >> expireMessagesPeriod (which is 30000). However, no advisory messages are >> produced with TTLs. >> >> I believe this is done in AdvisoryBroker.fireAdvisory >> >> … looking at this code, a TTL isn’t set. So I think that it would be a >> good idea to enable expireMessagesPeriod=0 for advisory topics. >> >> Here’s the code if you’re interested: >> >> http://pastebin.com/i3hXDGEW >> >> Looks like the following policyEntry works as a proof of concept. >> >> <policyEntry topic=">" >> prioritizedMessages="false" >> useCache="false" >> maxBrowsePageSize="2147483647" >> expireMessagesPeriod="0"> >> >> </policyEntry> >> >> (I am going to constrain it for advisory topics though). >> >> In my test time time for GCing all my queues went from 45s to 17s. It’s >> MUCH higher than this under production load though due threading issues. >> >> Are there any potential issues I might be missing here? >> >> If this works I might try to submit a patch to disable >> expireMessagesPeriod by default for advisory topics. >> >> -- >> >> Founder/CEO Spinn3r.com >> Location: *San Francisco, CA* >> blog: http://burtonator.wordpress.com >> … or check out my Google+ profile >> <https://plus.google.com/102718274791889610666/posts> >> >> > > > -- > > Founder/CEO Spinn3r.com > Location: *San Francisco, CA* > blog: http://burtonator.wordpress.com > … or check out my Google+ profile > <https://plus.google.com/102718274791889610666/posts> > > -- Founder/CEO Spinn3r.com Location: *San Francisco, CA* blog: http://burtonator.wordpress.com … or check out my Google+ profile <https://plus.google.com/102718274791889610666/posts>
