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Posted to dev@ofbiz.apache.org by Jacques Le Roux <ja...@les7arts.com> on 2009/09/23 10:38:03 UTC
Synchronisation issues
Hi,
I'm highly interested by the issues Philippe Mouawad created, notably
https://issues.apache.org/jira/browse/OFBIZ-2186
https://issues.apache.org/jira/browse/OFBIZ-2124
Also, but not directly related to Synchronisation issues in OFBiz
https://issues.apache.org/jira/browse/OFBIZ-2353 (waiting comments from Philippe)
https://issues.apache.org/jira/browse/OFBIZ-2599 (waiting action by DBCP team)
I trust Philippe and his colleagues since I know they worked on the optimisation of a large and successful OFBiz deployment.
David suggested successively 2 patches for OFBIZ-2186 but they did not fix the problem Philippe encountered. However Philippe's
patch did.
Since I'd like to fix these 2 issues in OFBiz (2124 and then 2186) but I have no time to set 2 machines and a load balancer for
these particular problems to test, I googled for "synchronized java performance"
and I found this article http://www.ibm.com/developerworks/java/library/j-jtp04223.html#N1005B by Brian Goetz who also wrote
http://www.javaconcurrencyinpractice.com/ (I did not read the book yet)
I read also in Sun documentation http://java.sun.com/developer/onlineTraining/Programming/JDCBook/perf2.html
"Synchronized methods and objects have until Java 2 always incurred an additional performance hit as the mechanism used to implement
the locking of this code used a global monitor registry which was only single threaded in some areas such as searching for existing
monitors. In the Java 2 release, each thread has a monitor registry and so many of the existing bottlenecks have been removed.
If you have previously used other locking mechanisms because of the performance hit with synchronized methods it is now worthwhile
re-visiting this code and incorporating the new Java 2 streamlined locks."
And also for Java 6 at http://java.sun.com/performance/reference/whitepapers/6_performance.html#2.1
So I would like to commit the patch I slightly modified in OFBIZ-2124
But before that I'd be interested to have some opinions by people who are using load balancers. Notably Brett who recently answered
about this subject on user ML. Because I wonder why Philippe was the 1st to discover theses issues and if others have fixed them in
another way.
Please comment
Thanks
Jacques
Re: Synchronisation issues
Posted by Jacques Le Roux <ja...@les7arts.com>.
Hi Pierre,
Thanks for you encouragements.
All,
I haven't close yet https://issues.apache.org/jira/browse/OFBIZ-2124 because hopefully Philippe will submit a patch for R4.0 (I
know this project used R4, and I guess it still do)
There is still a related issue opened https://issues.apache.org/jira/browse/OFBIZ-2186
>From Philippe informations I'd like to commit this patch also. I will do soon, except if someone see really something bad in it.
It's about possible synchronisation slowness, but as they checked it seriously (see last comment) I'm quite sure we can trust them.
Jacques
From: "pierre" <pi...@nereide.biz>
> Thank you very much for all this work Jacques!
>
> Pierre
> Jacques Le Roux a écrit :
>> Hi Pierre,
>>
>> Yes I know that. That's why I will commit soon... Tomorrow I guess, anyway it's there for months...
>>
>> Thanks!
>>
>> Jacques
>>
>> From: "pierre.gaudin" <pi...@nereide.fr>
>>> Hi Jacques,
>>>
>>> I know that it is not the proof that functions correctly but we work with Philippe on joint projects and the patchs have been in
>>> production on OFBiz for several months without any problems.
>>>
>>> Regards
>>>
>>> Pierre
>>> Jacques Le Roux a écrit :
>>>> Thanks for comment Adrian,
>>>>
>>>> I really think Philippe (and his team) has done a good work. I trust them and I'd like to put that in. I was looking for cons
>>>> if
>>>> any, else I will commit soon...
>>>>
>>>> Thanks
>>>>
>>>> Jacques
>>>>
>>>> From: "Adrian Crum" <ad...@yahoo.com>
>>>>> There is no doubt that there are synchronization issues in the Java code. I run across them all the time and fix them as I
>>>>> find
>>>>> them.
>>>>>
>>>>> Maybe this is a good time to start a synchronization "Best Practices" thread where we can all offer our insights and
>>>>> suggestions
>>>>> so that poorly synchronized code is easier to notice and correct.
>>>>>
>>>>> -Adrian
>>>>>
>>>>>
>>>>> --- On Sat, 11/14/09, Jacques Le Roux <ja...@les7arts.com> wrote:
>>>>>
>>>>>> From: Jacques Le Roux <ja...@les7arts.com>
>>>>>> Subject: Re: Synchronisation issues
>>>>>> To: dev@ofbiz.apache.org
>>>>>> Date: Saturday, November 14, 2009, 6:58 AM
>>>>>> From: "Adam Heath" <do...@brainfood.com>
>>>>>> >> But before that I'd be interested to have some
>>>>>> opinions by people who
>>>>>> >> are using load balancers. Notably Brett who
>>>>>> recently answered about this
>>>>>> >> subject on user ML. Because I wonder why Philippe
>>>>>> was the 1st to
>>>>>> >> discover theses issues and if others have fixed
>>>>>> them in another way.
>>>>>> >
>>>>>> > Using synchronization can cause deadlocks. If
>>>>>> you do not *fully*
>>>>>> > control *all* code that is run under synchronization,
>>>>>> then a deadlock
>>>>>> > can occur.
>>>>>>
>>>>>> I agree, synchronization is tricky. BTW, what to you think
>>>>>> about r751619 ? Here is a remark about it
>>>>>> https://issues.apache.org/jira/browse/OFBIZ-2186?focusedCommentId=12680105&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12680105
>>>>>>
>>>>>> > If you call some other library, and said library is
>>>>>> extensible, such
>>>>>> > that it might end up calling *back* into your code,
>>>>>> you *will* deadlock.
>>>>>>
>>>>>> I agree, but I don't think it concerns this problem (I
>>>>>> checked the Call Hierarchy)
>>>>>>
>>>>>> > Non-blocking algorythms don't have this problem,
>>>>>> because they retry in
>>>>>> > these cases.
>>>>>>
>>>>>> Sure, but a problem appeared here, it's well explained at
>>>>>> https://issues.apache.org/jira/browse/OFBIZ-2124 and
>>>>>> they propose a fix
>>>>>> that works.
>>>>>> It's not the 1st time this kind of problem appears. We have
>>>>>> an opportunity to try a fix, this is the pragmatic reason of
>>>>>> this
>>>>>> message. What make me worry is that I'm sure there are
>>>>>> other sites at least as much "big" as the one Philippe
>>>>>> speaks about (but it's
>>>>>> true it's a big one, at least in OFBiz world).
>>>>>>
>>>>>> Others opinions ?
>>>>>>
>>>>>> Jacques
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Pierre Gaudin,
>>> Consultant Fonctionnel Neogia, Apache-OFBiz
>>> ERP en logiciel Libre
>>>
>>> Société Néréide
>>> mobile : +33 (0)6 08 40 25 70
>>> bureau : +33 (0)2 47 50 30 54
>>> http://www.nereide.biz
>>>
>>
>>
>>
>
>
> --
> Pierre Gaudin,
> Consultant Fonctionnel Neogia, Apache-OFBiz
> ERP en logiciel Libre
>
> Société Néréide
> mobile : +33 (0)6 08 40 25 70
> bureau : +33 (0)2 47 50 30 54
> http://www.nereide.biz
>
Re: Synchronisation issues
Posted by pierre <pi...@nereide.biz>.
Thank you very much for all this work Jacques!
Pierre
Jacques Le Roux a écrit :
> Hi Pierre,
>
> Yes I know that. That's why I will commit soon... Tomorrow I guess,
> anyway it's there for months...
>
> Thanks!
>
> Jacques
>
> From: "pierre.gaudin" <pi...@nereide.fr>
>> Hi Jacques,
>>
>> I know that it is not the proof that functions correctly but we work
>> with Philippe on joint projects and the patchs have been in
>> production on OFBiz for several months without any problems.
>>
>> Regards
>>
>> Pierre
>> Jacques Le Roux a écrit :
>>> Thanks for comment Adrian,
>>>
>>> I really think Philippe (and his team) has done a good work. I trust
>>> them and I'd like to put that in. I was looking for cons if
>>> any, else I will commit soon...
>>>
>>> Thanks
>>>
>>> Jacques
>>>
>>> From: "Adrian Crum" <ad...@yahoo.com>
>>>> There is no doubt that there are synchronization issues in the Java
>>>> code. I run across them all the time and fix them as I find
>>>> them.
>>>>
>>>> Maybe this is a good time to start a synchronization "Best
>>>> Practices" thread where we can all offer our insights and suggestions
>>>> so that poorly synchronized code is easier to notice and correct.
>>>>
>>>> -Adrian
>>>>
>>>>
>>>> --- On Sat, 11/14/09, Jacques Le Roux
>>>> <ja...@les7arts.com> wrote:
>>>>
>>>>> From: Jacques Le Roux <ja...@les7arts.com>
>>>>> Subject: Re: Synchronisation issues
>>>>> To: dev@ofbiz.apache.org
>>>>> Date: Saturday, November 14, 2009, 6:58 AM
>>>>> From: "Adam Heath" <do...@brainfood.com>
>>>>> >> But before that I'd be interested to have some
>>>>> opinions by people who
>>>>> >> are using load balancers. Notably Brett who
>>>>> recently answered about this
>>>>> >> subject on user ML. Because I wonder why Philippe
>>>>> was the 1st to
>>>>> >> discover theses issues and if others have fixed
>>>>> them in another way.
>>>>> >
>>>>> > Using synchronization can cause deadlocks. If
>>>>> you do not *fully*
>>>>> > control *all* code that is run under synchronization,
>>>>> then a deadlock
>>>>> > can occur.
>>>>>
>>>>> I agree, synchronization is tricky. BTW, what to you think
>>>>> about r751619 ? Here is a remark about it
>>>>> https://issues.apache.org/jira/browse/OFBIZ-2186?focusedCommentId=12680105&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12680105
>>>>>
>>>>>
>>>>> > If you call some other library, and said library is
>>>>> extensible, such
>>>>> > that it might end up calling *back* into your code,
>>>>> you *will* deadlock.
>>>>>
>>>>> I agree, but I don't think it concerns this problem (I
>>>>> checked the Call Hierarchy)
>>>>>
>>>>> > Non-blocking algorythms don't have this problem,
>>>>> because they retry in
>>>>> > these cases.
>>>>>
>>>>> Sure, but a problem appeared here, it's well explained at
>>>>> https://issues.apache.org/jira/browse/OFBIZ-2124 and
>>>>> they propose a fix
>>>>> that works.
>>>>> It's not the 1st time this kind of problem appears. We have
>>>>> an opportunity to try a fix, this is the pragmatic reason of
>>>>> this
>>>>> message. What make me worry is that I'm sure there are
>>>>> other sites at least as much "big" as the one Philippe
>>>>> speaks about (but it's
>>>>> true it's a big one, at least in OFBiz world).
>>>>>
>>>>> Others opinions ?
>>>>>
>>>>> Jacques
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>
>>
>> --
>> Pierre Gaudin,
>> Consultant Fonctionnel Neogia, Apache-OFBiz
>> ERP en logiciel Libre
>>
>> Société Néréide
>> mobile : +33 (0)6 08 40 25 70
>> bureau : +33 (0)2 47 50 30 54
>> http://www.nereide.biz
>>
>
>
>
--
Pierre Gaudin,
Consultant Fonctionnel Neogia, Apache-OFBiz
ERP en logiciel Libre
Société Néréide
mobile : +33 (0)6 08 40 25 70
bureau : +33 (0)2 47 50 30 54
http://www.nereide.biz
Re: Synchronisation issues
Posted by Jacques Le Roux <ja...@les7arts.com>.
Hi Pierre,
Yes I know that. That's why I will commit soon... Tomorrow I guess, anyway it's there for months...
Thanks!
Jacques
From: "pierre.gaudin" <pi...@nereide.fr>
> Hi Jacques,
>
> I know that it is not the proof that functions correctly but we work with Philippe on joint projects and the patchs have been in
> production on OFBiz for several months without any problems.
>
> Regards
>
> Pierre
> Jacques Le Roux a écrit :
>> Thanks for comment Adrian,
>>
>> I really think Philippe (and his team) has done a good work. I trust them and I'd like to put that in. I was looking for cons if
>> any, else I will commit soon...
>>
>> Thanks
>>
>> Jacques
>>
>> From: "Adrian Crum" <ad...@yahoo.com>
>>> There is no doubt that there are synchronization issues in the Java code. I run across them all the time and fix them as I find
>>> them.
>>>
>>> Maybe this is a good time to start a synchronization "Best Practices" thread where we can all offer our insights and suggestions
>>> so that poorly synchronized code is easier to notice and correct.
>>>
>>> -Adrian
>>>
>>>
>>> --- On Sat, 11/14/09, Jacques Le Roux <ja...@les7arts.com> wrote:
>>>
>>>> From: Jacques Le Roux <ja...@les7arts.com>
>>>> Subject: Re: Synchronisation issues
>>>> To: dev@ofbiz.apache.org
>>>> Date: Saturday, November 14, 2009, 6:58 AM
>>>> From: "Adam Heath" <do...@brainfood.com>
>>>> >> But before that I'd be interested to have some
>>>> opinions by people who
>>>> >> are using load balancers. Notably Brett who
>>>> recently answered about this
>>>> >> subject on user ML. Because I wonder why Philippe
>>>> was the 1st to
>>>> >> discover theses issues and if others have fixed
>>>> them in another way.
>>>> >
>>>> > Using synchronization can cause deadlocks. If
>>>> you do not *fully*
>>>> > control *all* code that is run under synchronization,
>>>> then a deadlock
>>>> > can occur.
>>>>
>>>> I agree, synchronization is tricky. BTW, what to you think
>>>> about r751619 ? Here is a remark about it
>>>> https://issues.apache.org/jira/browse/OFBIZ-2186?focusedCommentId=12680105&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12680105
>>>>
>>>> > If you call some other library, and said library is
>>>> extensible, such
>>>> > that it might end up calling *back* into your code,
>>>> you *will* deadlock.
>>>>
>>>> I agree, but I don't think it concerns this problem (I
>>>> checked the Call Hierarchy)
>>>>
>>>> > Non-blocking algorythms don't have this problem,
>>>> because they retry in
>>>> > these cases.
>>>>
>>>> Sure, but a problem appeared here, it's well explained at
>>>> https://issues.apache.org/jira/browse/OFBIZ-2124 and
>>>> they propose a fix
>>>> that works.
>>>> It's not the 1st time this kind of problem appears. We have
>>>> an opportunity to try a fix, this is the pragmatic reason of
>>>> this
>>>> message. What make me worry is that I'm sure there are
>>>> other sites at least as much "big" as the one Philippe
>>>> speaks about (but it's
>>>> true it's a big one, at least in OFBiz world).
>>>>
>>>> Others opinions ?
>>>>
>>>> Jacques
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>
>
> --
> Pierre Gaudin,
> Consultant Fonctionnel Neogia, Apache-OFBiz
> ERP en logiciel Libre
>
> Société Néréide
> mobile : +33 (0)6 08 40 25 70
> bureau : +33 (0)2 47 50 30 54
> http://www.nereide.biz
>
Re: Synchronisation issues
Posted by "pierre.gaudin" <pi...@nereide.fr>.
Hi Jacques,
I know that it is not the proof that functions correctly but we work
with Philippe on joint projects and the patchs have been in production
on OFBiz for several months without any problems.
Regards
Pierre
Jacques Le Roux a écrit :
> Thanks for comment Adrian,
>
> I really think Philippe (and his team) has done a good work. I trust
> them and I'd like to put that in. I was looking for cons if
> any, else I will commit soon...
>
> Thanks
>
> Jacques
>
> From: "Adrian Crum" <ad...@yahoo.com>
>> There is no doubt that there are synchronization issues in the Java
>> code. I run across them all the time and fix them as I find
>> them.
>>
>> Maybe this is a good time to start a synchronization "Best Practices"
>> thread where we can all offer our insights and suggestions
>> so that poorly synchronized code is easier to notice and correct.
>>
>> -Adrian
>>
>>
>> --- On Sat, 11/14/09, Jacques Le Roux <ja...@les7arts.com>
>> wrote:
>>
>>> From: Jacques Le Roux <ja...@les7arts.com>
>>> Subject: Re: Synchronisation issues
>>> To: dev@ofbiz.apache.org
>>> Date: Saturday, November 14, 2009, 6:58 AM
>>> From: "Adam Heath" <do...@brainfood.com>
>>> >> But before that I'd be interested to have some
>>> opinions by people who
>>> >> are using load balancers. Notably Brett who
>>> recently answered about this
>>> >> subject on user ML. Because I wonder why Philippe
>>> was the 1st to
>>> >> discover theses issues and if others have fixed
>>> them in another way.
>>> >
>>> > Using synchronization can cause deadlocks. If
>>> you do not *fully*
>>> > control *all* code that is run under synchronization,
>>> then a deadlock
>>> > can occur.
>>>
>>> I agree, synchronization is tricky. BTW, what to you think
>>> about r751619 ? Here is a remark about it
>>> https://issues.apache.org/jira/browse/OFBIZ-2186?focusedCommentId=12680105&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12680105
>>>
>>>
>>> > If you call some other library, and said library is
>>> extensible, such
>>> > that it might end up calling *back* into your code,
>>> you *will* deadlock.
>>>
>>> I agree, but I don't think it concerns this problem (I
>>> checked the Call Hierarchy)
>>>
>>> > Non-blocking algorythms don't have this problem,
>>> because they retry in
>>> > these cases.
>>>
>>> Sure, but a problem appeared here, it's well explained at
>>> https://issues.apache.org/jira/browse/OFBIZ-2124 and
>>> they propose a fix
>>> that works.
>>> It's not the 1st time this kind of problem appears. We have
>>> an opportunity to try a fix, this is the pragmatic reason of
>>> this
>>> message. What make me worry is that I'm sure there are
>>> other sites at least as much "big" as the one Philippe
>>> speaks about (but it's
>>> true it's a big one, at least in OFBiz world).
>>>
>>> Others opinions ?
>>>
>>> Jacques
>>>
>>>
>>>
>>
>>
>>
>>
>
>
>
--
Pierre Gaudin,
Consultant Fonctionnel Neogia, Apache-OFBiz
ERP en logiciel Libre
Société Néréide
mobile : +33 (0)6 08 40 25 70
bureau : +33 (0)2 47 50 30 54
http://www.nereide.biz
Re: Synchronisation issues
Posted by Jacques Le Roux <ja...@les7arts.com>.
Thanks for comment Adrian,
I really think Philippe (and his team) has done a good work. I trust them and I'd like to put that in. I was looking for cons if
any, else I will commit soon...
Thanks
Jacques
From: "Adrian Crum" <ad...@yahoo.com>
> There is no doubt that there are synchronization issues in the Java code. I run across them all the time and fix them as I find
> them.
>
> Maybe this is a good time to start a synchronization "Best Practices" thread where we can all offer our insights and suggestions
> so that poorly synchronized code is easier to notice and correct.
>
> -Adrian
>
>
> --- On Sat, 11/14/09, Jacques Le Roux <ja...@les7arts.com> wrote:
>
>> From: Jacques Le Roux <ja...@les7arts.com>
>> Subject: Re: Synchronisation issues
>> To: dev@ofbiz.apache.org
>> Date: Saturday, November 14, 2009, 6:58 AM
>> From: "Adam Heath" <do...@brainfood.com>
>> >> But before that I'd be interested to have some
>> opinions by people who
>> >> are using load balancers. Notably Brett who
>> recently answered about this
>> >> subject on user ML. Because I wonder why Philippe
>> was the 1st to
>> >> discover theses issues and if others have fixed
>> them in another way.
>> >
>> > Using synchronization can cause deadlocks. If
>> you do not *fully*
>> > control *all* code that is run under synchronization,
>> then a deadlock
>> > can occur.
>>
>> I agree, synchronization is tricky. BTW, what to you think
>> about r751619 ? Here is a remark about it
>> https://issues.apache.org/jira/browse/OFBIZ-2186?focusedCommentId=12680105&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12680105
>>
>> > If you call some other library, and said library is
>> extensible, such
>> > that it might end up calling *back* into your code,
>> you *will* deadlock.
>>
>> I agree, but I don't think it concerns this problem (I
>> checked the Call Hierarchy)
>>
>> > Non-blocking algorythms don't have this problem,
>> because they retry in
>> > these cases.
>>
>> Sure, but a problem appeared here, it's well explained at
>> https://issues.apache.org/jira/browse/OFBIZ-2124 and
>> they propose a fix
>> that works.
>> It's not the 1st time this kind of problem appears. We have
>> an opportunity to try a fix, this is the pragmatic reason of
>> this
>> message. What make me worry is that I'm sure there are
>> other sites at least as much "big" as the one Philippe
>> speaks about (but it's
>> true it's a big one, at least in OFBiz world).
>>
>> Others opinions ?
>>
>> Jacques
>>
>>
>>
>
>
>
>
Re: Synchronisation issues
Posted by Adrian Crum <ad...@yahoo.com>.
There is no doubt that there are synchronization issues in the Java code. I run across them all the time and fix them as I find them.
Maybe this is a good time to start a synchronization "Best Practices" thread where we can all offer our insights and suggestions so that poorly synchronized code is easier to notice and correct.
-Adrian
--- On Sat, 11/14/09, Jacques Le Roux <ja...@les7arts.com> wrote:
> From: Jacques Le Roux <ja...@les7arts.com>
> Subject: Re: Synchronisation issues
> To: dev@ofbiz.apache.org
> Date: Saturday, November 14, 2009, 6:58 AM
> From: "Adam Heath" <do...@brainfood.com>
> >> But before that I'd be interested to have some
> opinions by people who
> >> are using load balancers. Notably Brett who
> recently answered about this
> >> subject on user ML. Because I wonder why Philippe
> was the 1st to
> >> discover theses issues and if others have fixed
> them in another way.
> >
> > Using synchronization can cause deadlocks. If
> you do not *fully*
> > control *all* code that is run under synchronization,
> then a deadlock
> > can occur.
>
> I agree, synchronization is tricky. BTW, what to you think
> about r751619 ? Here is a remark about it
> https://issues.apache.org/jira/browse/OFBIZ-2186?focusedCommentId=12680105&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12680105
>
> > If you call some other library, and said library is
> extensible, such
> > that it might end up calling *back* into your code,
> you *will* deadlock.
>
> I agree, but I don't think it concerns this problem (I
> checked the Call Hierarchy)
>
> > Non-blocking algorythms don't have this problem,
> because they retry in
> > these cases.
>
> Sure, but a problem appeared here, it's well explained at
> https://issues.apache.org/jira/browse/OFBIZ-2124 and
> they propose a fix
> that works.
> It's not the 1st time this kind of problem appears. We have
> an opportunity to try a fix, this is the pragmatic reason of
> this
> message. What make me worry is that I'm sure there are
> other sites at least as much "big" as the one Philippe
> speaks about (but it's
> true it's a big one, at least in OFBiz world).
>
> Others opinions ?
>
> Jacques
>
>
>
Re: Synchronisation issues
Posted by Jacques Le Roux <ja...@les7arts.com>.
From: "Adam Heath" <do...@brainfood.com>
>> But before that I'd be interested to have some opinions by people who
>> are using load balancers. Notably Brett who recently answered about this
>> subject on user ML. Because I wonder why Philippe was the 1st to
>> discover theses issues and if others have fixed them in another way.
>
> Using synchronization can cause deadlocks. If you do not *fully*
> control *all* code that is run under synchronization, then a deadlock
> can occur.
I agree, synchronization is tricky. BTW, what to you think about r751619 ? Here is a remark about it
https://issues.apache.org/jira/browse/OFBIZ-2186?focusedCommentId=12680105&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12680105
> If you call some other library, and said library is extensible, such
> that it might end up calling *back* into your code, you *will* deadlock.
I agree, but I don't think it concerns this problem (I checked the Call Hierarchy)
> Non-blocking algorythms don't have this problem, because they retry in
> these cases.
Sure, but a problem appeared here, it's well explained at https://issues.apache.org/jira/browse/OFBIZ-2124 and they propose a fix
that works.
It's not the 1st time this kind of problem appears. We have an opportunity to try a fix, this is the pragmatic reason of this
message. What make me worry is that I'm sure there are other sites at least as much "big" as the one Philippe speaks about (but it's
true it's a big one, at least in OFBiz world).
Others opinions ?
Jacques
Re: Synchronisation issues
Posted by Adam Heath <do...@brainfood.com>.
> But before that I'd be interested to have some opinions by people who
> are using load balancers. Notably Brett who recently answered about this
> subject on user ML. Because I wonder why Philippe was the 1st to
> discover theses issues and if others have fixed them in another way.
Using synchronization can cause deadlocks. If you do not *fully*
control *all* code that is run under synchronization, then a deadlock
can occur.
If you call some other library, and said library is extensible, such
that it might end up calling *back* into your code, you *will* deadlock.
Non-blocking algorythms don't have this problem, because they retry in
these cases.