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Posted to users@tomcat.apache.org by Jonathan Yom-Tov <jo...@sysaid.com> on 2020/05/18 14:23:36 UTC
persistentmanager loads only part of session?
Here's my setup: I have two Tomcats using PersistentManager with FileStore
to store sessions on a NFS they both have access to. Inside the session
there's an object which contains a map. I also have a request listener that
logs the contents of the map on every request.
I kill one Tomcat and I can see in the session file that the map contains
two keys. I then make a request to the remaining Tomcat and I can see the
map contains only one key.
The only way I can think of that that would happen is if the map was only
partially loaded from the file. Is that even possible? Any good ideas on
how to debug this?
Re: persistentmanager loads only part of session?
Posted by Jonathan Yom-Tov <jo...@sysaid.com>.
I don't think that can happen. I'm using sticky session so the first server
gets all requests, then I kill it and only then are requests routed to the
second server.
On Mon, 18 May 2020, 21:15 Christopher Schultz, <
chris@christopherschultz.net> wrote:
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> Hash: SHA256
>
> Jonathan,
>
> On 5/18/20 12:52, Jonathan Yom-Tov wrote:
> > I see the persisted copy in the file and it has two keys, so I
> > don't think that's it. It's probably some sort of parallelism issue
> > since it happens only occasionally, but the map is a
> > ConcurrentHashMap, so I can't see how it would be overwritten.
>
> What happens if both servers write the file at the same time?
>
> - -chris
>
> > On Mon, 18 May 2020, 19:47 Mark Thomas, <ma...@apache.org> wrote:
> >
> >> On 18/05/2020 15:23, Jonathan Yom-Tov wrote:
> >>> Here's my setup: I have two Tomcats using PersistentManager
> >>> with
> >> FileStore
> >>> to store sessions on a NFS they both have access to. Inside the
> >>> session there's an object which contains a map. I also have a
> >>> request listener
> >> that
> >>> logs the contents of the map on every request.
> >>>
> >>> I kill one Tomcat and I can see in the session file that the
> >>> map contains two keys. I then make a request to the remaining
> >>> Tomcat and I can see the map contains only one key.
> >>>
> >>> The only way I can think of that that would happen is if the
> >>> map was only partially loaded from the file. Is that even
> >>> possible? Any good ideas on how to debug this?
> >>
> >> Best guess you add the Map containing one key to the session and
> >> then later add a second key the Map. Tomcat doesn't consider the
> >> session to be updated when the second key is added so the
> >> persisted copy doesn't get updated.
> >>
> >> Mark
> >>
> >>
> >> ---------------------------------------------------------------------
> >>
> >>
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> >> For additional commands, e-mail: users-help@tomcat.apache.org
> >>
> >>
> >
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> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
>
Re: persistentmanager loads only part of session?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
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Hash: SHA256
Jonathan,
On 5/18/20 12:52, Jonathan Yom-Tov wrote:
> I see the persisted copy in the file and it has two keys, so I
> don't think that's it. It's probably some sort of parallelism issue
> since it happens only occasionally, but the map is a
> ConcurrentHashMap, so I can't see how it would be overwritten.
What happens if both servers write the file at the same time?
- -chris
> On Mon, 18 May 2020, 19:47 Mark Thomas, <ma...@apache.org> wrote:
>
>> On 18/05/2020 15:23, Jonathan Yom-Tov wrote:
>>> Here's my setup: I have two Tomcats using PersistentManager
>>> with
>> FileStore
>>> to store sessions on a NFS they both have access to. Inside the
>>> session there's an object which contains a map. I also have a
>>> request listener
>> that
>>> logs the contents of the map on every request.
>>>
>>> I kill one Tomcat and I can see in the session file that the
>>> map contains two keys. I then make a request to the remaining
>>> Tomcat and I can see the map contains only one key.
>>>
>>> The only way I can think of that that would happen is if the
>>> map was only partially loaded from the file. Is that even
>>> possible? Any good ideas on how to debug this?
>>
>> Best guess you add the Map containing one key to the session and
>> then later add a second key the Map. Tomcat doesn't consider the
>> session to be updated when the second key is added so the
>> persisted copy doesn't get updated.
>>
>> Mark
>>
>>
>> ---------------------------------------------------------------------
>>
>>
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
>> For additional commands, e-mail: users-help@tomcat.apache.org
>>
>>
>
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Re: persistentmanager loads only part of session?
Posted by Jonathan Yom-Tov <jo...@sysaid.com>.
I see the persisted copy in the file and it has two keys, so I don't think
that's it. It's probably some sort of parallelism issue since it happens
only occasionally, but the map is a ConcurrentHashMap, so I can't see how
it would be overwritten.
On Mon, 18 May 2020, 19:47 Mark Thomas, <ma...@apache.org> wrote:
> On 18/05/2020 15:23, Jonathan Yom-Tov wrote:
> > Here's my setup: I have two Tomcats using PersistentManager with
> FileStore
> > to store sessions on a NFS they both have access to. Inside the session
> > there's an object which contains a map. I also have a request listener
> that
> > logs the contents of the map on every request.
> >
> > I kill one Tomcat and I can see in the session file that the map contains
> > two keys. I then make a request to the remaining Tomcat and I can see the
> > map contains only one key.
> >
> > The only way I can think of that that would happen is if the map was only
> > partially loaded from the file. Is that even possible? Any good ideas on
> > how to debug this?
>
> Best guess you add the Map containing one key to the session and then
> later add a second key the Map. Tomcat doesn't consider the session to
> be updated when the second key is added so the persisted copy doesn't
> get updated.
>
> Mark
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
>
Re: persistentmanager loads only part of session?
Posted by Mark Thomas <ma...@apache.org>.
On 18/05/2020 15:23, Jonathan Yom-Tov wrote:
> Here's my setup: I have two Tomcats using PersistentManager with FileStore
> to store sessions on a NFS they both have access to. Inside the session
> there's an object which contains a map. I also have a request listener that
> logs the contents of the map on every request.
>
> I kill one Tomcat and I can see in the session file that the map contains
> two keys. I then make a request to the remaining Tomcat and I can see the
> map contains only one key.
>
> The only way I can think of that that would happen is if the map was only
> partially loaded from the file. Is that even possible? Any good ideas on
> how to debug this?
Best guess you add the Map containing one key to the session and then
later add a second key the Map. Tomcat doesn't consider the session to
be updated when the second key is added so the persisted copy doesn't
get updated.
Mark
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