peek at org.apache.activemq.broker.region.cursors.VMPendingMessageCursor and the use of PrioritizedPendingList
On 6 April 2015 at 22:57, Kevin Burton <bur...@spinn3r.com> wrote: > How are messages served now.. I *think* they’re served based on message ID > and sequence and served with the lowest ID first. Which is why a map > works..but it means that I can’t re-implement this using just a queue > sorted by priorities and a comparator. > > I spent about 5 minutes looking at how KahaDB implements it and it looks > like it’s just using the btree and that the cursor implements the priority > support. > > > > > On Mon, Apr 6, 2015 at 2:38 PM, Timothy Bish <tabish...@gmail.com> wrote: > >> On 04/06/2015 05:05 PM, Kevin Burton wrote: >> > So I’m torn between two implementations of a new MemoryStore using JMS >> > priority. >> > >> > I could do it the FAST way, and use just a regular queue object, which >> > would include support for priorities, BUT would be slower for certain >> > operations like remove, get, and maybe size. >> > >> > It would just use a PriorityBlockingQueue >> > >> > OR >> > >> > I could do it the SLOW (and somewhat ugly) way but make it more >> compatible >> > with what works now. Basically I would use a ReentrantReadWriteLock >> around >> > both a map and a queue. The queue would be used or (obvious) queue >> > operations but the map would be used for getMessage and remove() … It >> would >> > also work with topics. >> > >> > The FAST way above wouldn’t work well with getMessage… because I would >> have >> > to iterate over the whole queue and then compare each message. >> > >> > I guess maybe the best way to go is to be conservative/pragmatic here and >> > move to a ReentrantReadWrite lock model and use both a map and a queue. >> > This would prevent any weird behavior that I don’t anticipate in exchange >> > for speed. It would also mean it would work well for topics too. >> I'd go with the second option as you still want to management operations >> to perform in a reasonable fashion even with the memory store. >> >> -- >> Tim Bish >> Sr Software Engineer | RedHat Inc. >> tim.b...@redhat.com | www.redhat.com >> twitter: @tabish121 >> blog: http://timbish.blogspot.com/ >> >> > > > -- > > 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> > <http://spinn3r.com>
