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Hi
Andreas, we do caching this way, therefore having a single cache per JVM (our
app is running in a farm of 5 Web/App servers--Orion).
It's
great for read-only operations; some servers (Orion is one of them) do this
caching for you, granted you give a single instance of the server EXCLUSIVE
write access to the DB; therefore, we implemented our own, read-only, in-memory
caching gear. If you use VO's, the problem is trivial -- as long as the cache is
for read-only data.
HTH,
JP
PS:
BTW, the app powers a web site with 10 M hits/week, so I guess we could call it
a "real-life application"... ;-)
Hi Dear All,
being a newbee to EJB I hope the
following questions don't bother you: :-)
I have a static
class XYZData with a static Vector containing some data. The
Vector acts like a cache. If I request some record from the
class,
it first searches
the Vector. If there is no matching record it is loaded from the Database and
appended to the list.
Now I have a stateless session bean which imports this class. There is a method which
calls the static method of the class XYZData to request
records.
The questions are:
How many
instances of the class XYZData (and the cached data) are created by an
Application Server if it creates multiple instances
of the session bean?
Is this a valid
design to implement a (read-only) cache in EJB? Are there better ways? (Using
"read-only entity beans" seems to be very vendor-specific.)
I read so
many docs - but a real answer to caching I never found. But I can't
imagine a "real-life application" without extensive caching.
In our
application we have country data, currency data, configuration data, language
data... lots of data which may be configured by the end user.
But after
beeing configurated this data remains unchanged for months.
What's the
answer to this type of problem? I'm very frustated about this. There is so
much effort and rumor about CMP. But in my opinion CMP (at this
time) doesn't help you to actually solve problems. No doubt, is has
many advantages and is a fine idea - but complex problems become not
really easier. (Foreign key relations appear to be a pain, there is one
more query language, performance is also a problem, ...)
In comparison caching of data appears to be a very trivial
problem. But I don't see any c l e a n way to implement
it.
Please help!
Thank you
much,
Andreas Maschke
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