How does the session know to replicate an object that's changing? For example, if during a request/response a mutator method is called on that object?
This is the problem. The session doesn't know, in this situation.
The only time a (key, object) pair in a session gets replicated is if Session.set...() has been called for that pair during this request/response cycle.
If you call a mutator on an object (where that object
has been pulled out of the session), then that mutated copy of the object WILL NOT be replicated unless you call Session.set...() again!
This is something that can really kill you when you try to deploy an app that works well in a non-clustered environment into a cluster.
Clustering *is* hard. And even the best application server in the world can't reduce that complexity. It can just try to not add any complexity of it's own.
Front-end load balancing, internal load balancing policy, cache settings, fail-over settings, setting up the LAN correctly... these are all *extra* things you need to do under a clustered J2EE server that you don't need to worry about normally. Clustering is hard
Having said that, I've been involved in commercial projects using clustering under Weblogic and JBoss. We have been able to get them going without too much trouble.
Also, some things J2EE allows some things in non-clustered mode that it explicity warns won't work in clustered mode. For example, objects in Sessions must be Serializable when clustering.
Interwoven's press release regarding their patent states the following 6 claims (of 13 claims). I have quoted each claim as described in their press release, and then shown how CVS can be used to show prior-art over the claim.
(And it only took me half an hour and a little googling to work all this out...)
I'm a software engineer (coder), but have mostly worked for small companies, where I find you always have to do a little 'management' here and there if you are one of the senior techies.
There are a couple of books that I have read that have given me real insight and inspiration into the whole software management thing (I say 'inspiration' since with software projects being "always late", who would want to be managing them!)
The first is "Debugging the Development Process" by Steve Maguire (ISBN: 1556156502).
This is a great book! Even if your company doesn't follow the development strategies he outlines, the team management strategies are great!
Steve is also the one that wrote 'Code Complete'; Steve is someone who started a techie and then learnt all sorts of things about running software projects.
While I'm on Steve's bandwangon, I *highly* recommend "Software Project Survival Guide" (ISBN: 1572316217). An awesome read.
(Also, while you are at it, checkout out his other books, I've got them all and they are quite good).
The other book I'd recommend is "AntiPatterns: Refactoring Software, Architectures, and Projects in Crisis" (ISBN: 0471197130). As well as having some great techie-level advice, it has some interesting management-level rules-of-thumb that no-one in the software profession (techie or not) should be without.
Slashdot Mirror
Putting swap in a RAM disk makes no sense what-so-ever.
Yep, you've hit upon the clincher.
This is the problem. The session doesn't know, in this situation.
The only time a (key, object) pair in a session gets replicated is if Session.set...() has been called for that pair during this request/response cycle.
If you call a mutator on an object (where that object has been pulled out of the session), then that mutated copy of the object WILL NOT be replicated unless you call Session.set...() again!
This is something that can really kill you when you try to deploy an app that works well in a non-clustered environment into a cluster.
Clustering *is* hard. And even the best application server in the world can't reduce that complexity. It can just try to not add any complexity of it's own.
Front-end load balancing, internal load balancing policy, cache settings, fail-over settings, setting up the LAN correctly... these are all *extra* things you need to do under a clustered J2EE server that you don't need to worry about normally. Clustering is hard
Having said that, I've been involved in commercial projects using clustering under Weblogic and JBoss. We have been able to get them going without too much trouble.
Also, some things J2EE allows some things in non-clustered mode that it explicity warns won't work in clustered mode. For example, objects in Sessions must be Serializable when clustering.
=Matt
Interwoven's press release regarding their patent states the following 6 claims (of 13 claims). I have quoted each claim as described in their press release, and then shown how CVS can be used to show prior-art over the claim.
(And it only took me half an hour and a little googling to work all this out...)
(read above blog entry for details)
There are a couple of books that I have read that have given me real insight and inspiration into the whole software management thing (I say 'inspiration' since with software projects being "always late", who would want to be managing them!)
The first is "Debugging the Development Process" by Steve Maguire (ISBN: 1556156502). This is a great book! Even if your company doesn't follow the development strategies he outlines, the team management strategies are great! Steve is also the one that wrote 'Code Complete'; Steve is someone who started a techie and then learnt all sorts of things about running software projects.
While I'm on Steve's bandwangon, I *highly* recommend "Software Project Survival Guide" (ISBN: 1572316217). An awesome read.
(Also, while you are at it, checkout out his other books, I've got them all and they are quite good).
The other book I'd recommend is "AntiPatterns: Refactoring Software, Architectures, and Projects in Crisis" (ISBN: 0471197130). As well as having some great techie-level advice, it has some interesting management-level rules-of-thumb that no-one in the software profession (techie or not) should be without.
Good luck, hope that helps!