Slightly off topic but... I'm going to try using cjdbc
(http://forge.objectweb.org/projects/c-jdbc) to connect a JDBCStore to two databases
in order to create a fault tolerant webdav service. There will also be two slide
servers:
-------- --------
| slide | | slide |
| server | | server |
| 1 | | 2 |
-------- --------
| |
-------- --------
| CJDBC |----| CJDBC |
--------\ /--------
| \ / |
| \/ |
-------- /\ --------
| DB1 |/ \| DB2 |
-------- --------
If one slide server or one database becomes unavailable the system will still be
operational. In order for this to work neither slide server should cache (if 1 updates
the db and 2 has a cached version, 2 will not see the update).
I had a quick look at the src for slide 2.0 and it looks like caching is not
configurable (cacheResults returns true in
org/apache/slide/common/AbstractServiceBase.java). So, just to confirm, in order to
switch caching off I will have to extend JDBCStore and overide cacheResults to return
false?
In addition I would be interested if anyone has any feedback on the above architecture
(eg will it work?). It does not have to be super responsive but must be fault tolerant
because, if all goes well, many other business critical systems will be relying on the
system availability.
Regards,
Jamie.
-----Original Message-----
From: Andreas Probst [mailto:[EMAIL PROTECTED]
Sent: 08 July 2004 06:35
To: Slide Developers Mailing List
Subject: Re: StandardStore, AbstractStore, caching
Hi Oliver,
thank you for the quick response. Sorry, but I copied it from
cvs head. It's not fixed there. Below are the ID tags.
/home/cvspublic/jakarta-slide/src/share/org/apache/slide/store/AbstractStore.java,v
1.42 2004/06/23 09:13:42 ozeigermann Exp $
/home/cvspublic/jakarta-slide/src/share/org/apache/slide/store/StandardStore.java,v
1.22 2004/02/11 11:30:18 ozeigermann Exp $
Regards,
Andreas
On 7 Jul 2004 at 23:54, Oliver Zeigermann wrote:
> Andreas Probst wrote:
> > for the project I'm working in I need to change the caching
> > behaviour of Slide. Looking at StandardStore, which does the
> > caching, I wonder:
> >
> > If caching is disabled, read calls are forwarded to super
> > (AbstractStore), which then calls the actual Store
> > implementation.
> >
> > If caching is enabled but the object to read is not in the
> > cache, the calls are not forwarded to super but to the actual
> > Store implementation, e.g. DescriptorsStore.
> >
> > Why is it done this way? Is it just style?
> > When super is called, the Stores are listed in a transaction...
>
> I guess you are referring to 2.0, right? I have done this stuff and as
> far as I remember, it was just non sense and I fixed it in the current
> CVS head.
>
> Oliver
>
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