Replacing our Replicated Caches with Distributed+CQC

Hi,
I've been advised on this forum to replace our Replicated caches with Distributed+CQC with an AlwaysFilter. This should give me the "zero-latency" get() performance which really should be part of a Replicated Cache, but apparently isn't (the lease-model and serialization get in the way of this).
My concern is now storage efficiency - my understanding is that my storage footprint will double, as the same information is now stored in two places (partitioned backing map and cqc front map). Is this correct? If so, I'm unsure why it would be considered a good replacement for the Replicated scheme.
Thanks,
Matt

The second link looks like it helped you out
- Re: The effects of "leases" on the read-performance of Replicated Caches
Also if you are looking at (near) zero latency when garbage collections occur, you might want to have at the Zing JVM
- http://www.azulsystems.com/products/zing/virtual-machine
Layency due to garbage collection (i.e., introduced pause times) could break your (extreme) low-latency demand.
You could try the CQC with the always filter:
NamedCache cache = CacheFactory.getCache("somecache");
ContinuousQueryCache localCache =new ContinousQueryCache(cache, AlwaysFilter.INSTANCE);The preceding code will result in a locally materialized view of the cache data that satisfies the specified filter. By default, both keys and values will be cached locally.
If you want to cache only keys and retrieve values from the back cache as needed, which might be the best option if the values are large and accessed infrequently, or
if you only care about having an up-to-date keyset locally, you can pass false as the third argument to the CQC constructor.
To get data from the CQC you can use
Iterator<Map.Entry<Integer, Klant>> data = localCache.entrySet().iterator();

Similar Messages

Read through Scheme in Replicated Cache with berkely db

Hi i have a 20 gb of data, while restarting the server i need to populate all the data in to coherence cache.if i create a pre load java class hadrly it will take 30 mins to 1 hour to load the data in to cache, while loading time if any request came means how can give the response to the request. i have gone through the Read through scheme its good. But i dont know how to implement with replicated cahce. is it possible to implement the read through+replicated cache+berkeley. if yes menas please post the sample code with full reference. thanks in advance
Edited by: 875786 on Dec 5, 2011 8:10 PM

If you read the documentation for the replicated scheme configuration here: http://docs.oracle.com/cd/E24290_01/coh.371/e22837/appendix_cacheconfig.htm#BABGHEJE ans specifically the part about the <backing-map> configutation you will see...
http://docs.oracle.com/cd/E24290_01/coh.371/e22837/appendix_cacheconfig.htm#BABGHEJE:
To ensure cache coherence, the backing-map of a replicated cache must not use a read-through pattern to load cache entries. Either use a cache-aside pattern from outside the cache service, or switch to the distributed-scheme, which supports read-through clustered caching.So it would appear that you cannot do read-through with a replicated cache - which makes sense really when you think about it.
As I already asked - why are you trying to put 20GB in a replicated cache?
Presumably you do not have JVMs with heaps well over 20GB to hold all that data, or do you - in which case you must have tuned GC very well. You say you are bothered about NFRs and network latency yet you are building a system that will require either very big heaps, and hence at some point there will be long GCs or you cannot hold all the data in memory so you have to configure expiry and then you have the latency of reading the data from the DB.
If you are using read-through then presumably your use-case does not require all the data to be in the cache - i.e. all you data access is using a get by key and you do not do any filter queries. If this is the case then use a distributed cache where you can store all the data or use read-through. If all you access is using key based gets then you do not need to co-locate the caches and your application in a single JVM - have separate cache server JVMs to hold the data and configure near-caches in your application.
There are various ways to hold 20GB of data that would be much more efficient than you are suggesting with a replicated cache.
JK

Replicated cache with cache store configuration

Hi All,
I am having two different applications. One is Admin kind of module from where data will be insterted/updated and another application will read data from Coherence cache.
My requirement is to use Replicated cache and data also needs to be stored in the database. I am configuring cache with cache store DB operation.
I have following coherence configuration. It works fine. Other application is able to read updated data. But while second application is trying to join the first application coherence cluster I am getting following exception in cache store. If I use distributed cache the same cache store works fine without any issues.
Also note that eventhough it is throwing exception, application is working fine as expected. Other thing I am pre loading data on application start up in first application.
Let me know if you need any further information.
Thanks in advance.
coherence-cache-config.xml
<?xml version="1.0"?>
<!DOCTYPE cache-config SYSTEM "cache-config.dtd">
<cache-config>
<caching-scheme-mapping>
<cache-mapping>
<cache-mapping>
<cache-name>TestCache</cache-name>
<scheme-name>TestCacheDB</scheme-name>
</cache-mapping>
</caching-scheme-mapping>
<caching-schemes>
<replicated-scheme>
<scheme-name>TestCacheDB</scheme-name>
<service-name>ReplicatedCache</service-name>
<backing-map-scheme>
<local-scheme>
<scheme-name>TestDBLocal</scheme-name>
<cachestore-scheme>
<class-scheme>
<class-name>test.TestCacheStore</class-name>
<init-params>
<init-param>
<param-type>java.lang.String</param-type>
<param-value>TEST_SUPPORT</param-value>
</init-param>
</init-params>
</class-scheme>
</cachestore-scheme>
</local-scheme>
</backing-map-scheme>
<listener/>
<autostart>true</autostart>
</replicated-scheme>

<proxy-scheme>
<scheme-name>proxy</scheme-name>
<service-name>ProxyService</service-name>
<thread-count system-property="tangosol.coherence.extend.threads">10</thread-count>
<acceptor-config>
<tcp-acceptor>
<local-address>
<address system-property="tangosol.coherence.extend.address">localhost</address>
<port system-property="tangosol.coherence.extend.port">7001</port>
<reusable>true</reusable>
</local-address>
</tcp-acceptor>
<serializer>
<class-name>com.tangosol.io.pof.ConfigurablePofContext</class-name>
<init-params>
<init-param>
<param-type>String</param-type>
<param-value>pof-config.xml</param-value>
</init-param>
</init-params>
</serializer>
</acceptor-config>
<autostart system-property="tangosol.coherence.extend.enabled">false</autostart> </proxy-scheme>
</caching-schemes>
</cache-config>
Exception:
2010-08-31 10:46:09.062/171.859 Oracle Coherence GE 3.5.2/463 <Error> (thread=ReplicatedCache, member=2): java.lang.Clas
sCastException: com.tangosol.util.Binary cannot be cast to test.TestBean
at test.TestCacheStore.store(TestCacheStore.java:137)
at com.tangosol.net.cache.LocalCache$InternalListener.onModify(LocalCache.java:637)
at com.tangosol.net.cache.LocalCache$InternalListener.entryInserted(LocalCache.java:599)
at com.tangosol.util.MapEvent.dispatch(MapEvent.java:206)
at com.tangosol.util.MapEvent.dispatch(MapEvent.java:166)
at com.tangosol.util.MapListenerSupport.fireEvent(MapListenerSupport.java:556)
at com.tangosol.net.cache.OldCache.dispatchEvent(OldCache.java:1916)
at com.tangosol.net.cache.OldCache$Entry.onAdd(OldCache.java:1985)
at com.tangosol.util.SafeHashMap.put(SafeHashMap.java:244)
at com.tangosol.net.cache.OldCache.put(OldCache.java:266)
at com.tangosol.coherence.component.util.CacheHandler.onLeaseUpdate(CacheHandler.CDB:42)
at com.tangosol.coherence.component.util.CacheHandler.populateCache(CacheHandler.CDB:33)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.ReplicatedCache$CacheUpdate.onReceiv
ed(ReplicatedCache.CDB:5)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.onMessage(Grid.CDB:9)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Grid.onNotify(Grid.CDB:136)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.ReplicatedCache.onNotify(ReplicatedC
ache.CDB:3)
at com.tangosol.coherence.component.util.Daemon.run(Daemon.CDB:42)
at java.lang.Thread.run(Thread.java:619)
2010-08-31 10:46:09.203/216.735 Oracle Coherence GE 3.5.2/463 <D5> (thread=DistributedCache, member=2): Deferring the di
stribution due to 128 pending configuration updates
TestBean.java
public class TestBean implements PortableObject, Serializable {
     private static final long serialVersionUID = 1L;
     private String name;
     private String number;
     private String taskType;
     public String getName() {
          return name;
     public void setName(String name) {
          this.name = name;
     public String getNumber() {
          return productId;
     public void setNumber(String number) {
          this.number= number;
     public String getTaskType() {
          return taskType;
     public void setTaskType(String taskType) {
          this.taskType = taskType;
     @Override
     public void readExternal(PofReader reader) throws IOException {
          name = reader.readString(0);
          number = reader.readString(1);
          taskType = reader.readString(2);
     @Override
     public void writeExternal(PofWriter writer) throws IOException {
          writer.writeString(0, name);
          writer.writeString(1, number);
          writer.writeString(2, taskType);
TestCacheStore.java
public class TestCacheStore extends Base implements CacheStore {
     @Override
     public void store(Object oKey, Object oValue) {
     if(logger.isInfoEnabled())
          logger.info("store :"+oKey);
     TestBean testBean = (TestBean)oValue; //Giving classcast exception here
//Doing some processing here over testBean
          ConnectionFactory connectionFactory = ConnectionFactory.getInstance();
          //Get the Connection
          Connection con = connectionFactory.getConnection();
          if(con != null){
//Code to insert into the database
          }else{
               logger.error("Connection is NULL");
Edited by: user8279242 on Aug 30, 2010 11:44 PM

Hello,
The problem is that replicated caches are not supported with read write backing maps.
Please refer to the link below for more information.
http://download.oracle.com/docs/cd/E15357_01/coh.360/e15723/cache_rtwtwbra.htm#CFHEJHCI
Best regards,
-Dave

Replicated Cache Data Visibility

Hello
When is the cache entry visible when doing a put(..) to a Replicated cache?
I've been reading the documentation for the Replicated Cache Topology, and it's not clear when data that has been put(..) is visible to other nodes.
For example, if I have a cluster comprised of 26 nodes (A through Z), and I invoke replicatedCache.put("foo", "bar") from member A, at what point is the Map.Entry("foo", "bar") present and queryable on member B? Is it as soon as it has been put into the local storage on B? Or is it only just before the call to put(..) on member A returns successfully? While the put(..) from member A is "in flight", is it possible to have to simultaneous reads on members F and Y return different results because the put(..) hasn't yet been invoked successfully on one of the nodes?
Regards
Pete

Hi Pete,
As the data replication is done asynchronously, (you may refer to this post, Re: Performance of replicated cache vs. distributed cache ) . So, you may read a different result on different nodes.
Furthermore, may I know your use case on replicated cache?
Regards,
Rock
Oracle ACS

Replacement of Test Db with Production Db

Hi,
Can anyone tell me what I should expect to break when I replace our Test db with a new copy of the Production db? Please note, I am NOT touching the Web db at all. I noticed the first time I did this, the parts images no longer displayed on the website. I am not sure why this was. If I looked at the Media area for a part, the image filename was still there but the image would not display on the website until it was reselected and resaved. I would not have expected this to happen. Once we are ready to go live, are we going to have to reselect all of the images for each part again?? I cannot believe that would be the way this is going to work.
I guess, in short, what could possibly break on the website from simply restoring an updated SAP database so our test db which is synching with the web db is more aligned with the production data so we can continue to tweak things before going live?
Thanks,
David

Hi James,
As per your instructions, this is what I did this evening. I made a backup of our Production database and restored it over top of our Test database. I opened Synch Manager and did an Initialize, then a Synch. When I opened the website, the images were again missing. If I go into a part under the Admin - Catalog area, the part still had the Additional Image link but the Image Path itself had been cleared out. All of our images are in the //assets/catalog/parts folder as you noted they should be.
Any other ideas why we would lose the main images? As I mentioned before, we need to get this resolved while we are still in our testing phase - we cannot afford to lose all of the image links once we switch the database to go live.
Thanks,
David

Basic use of locks with replicated cache

Hi,
I'm in the process of evaluating Coherence and I have a few fundamental questions about best locking practices with a simple replicated cache. I've been through the docs & forums a few times, but I'm still confused.
The docs say that a replicted cache is "fully coherent". What, exactly does this mean? Does this imply that Coherence handles all the locking for you? Under what situations do I have to lock a node?
Thanks.

Hi,
There are generally two reasons for desiring full synchronicity:
Fault tolerance ... however, note that by the time the put returns, the data is held by both the client and the issuer. Also, we recommend the use of the Distributed cache topology for transactional data (and not Replicated). Distributed is in fact fully synchronous.
The other reasons people usually ask about this is concern over the logical view of data updates (simultaneous state across the cluster). Even within a single JVM running on a single CPU, data updates are not simultaneous or even synchronous. This is quite intentional (in fact most of the complexity of the Java Memory Model arises from the desire to avoid the requirement for simultaneous state changes).
In the JVM, synchronized blocks are required to avoid race conditions and inconsistent views of data, and in Coherence, locks are required to do the same.
The key point to remember is, from the point of view of a single cluster member, data updates are in fact synchronous and simultaneous (with or without locking).
I'm assuming your question relates to one of those two issues (as those are the most common concerns that we hear); if not, could you provide a bit more background on your requirements?
Jon Purdy
Tangosol, Inc.

Using Mac OSX 10.7.1: recently replaced our DSL modum & wireless router and suddently I can't get some web sites to load. Many do, but Twitter and others often do not. I've reset the browsing historty, forms, cookies and cache but it continues to happen.

Using Mac OSX 10.7.1: recently replaced our DSL modum and wireless router, suddenly I can't get some web sites to load. Many do, but Twitter and others often do not. I've reset the browsing history, forms, cookies and cache but it continues to happen.

Ok, first thing, why are you doing anything with WAMP or XAMPP when you're running a Mac? MAMP should be what you want unless you're not explaining part of what you are trying to do.
2nd thing, I haven't used MAMP in a while, but there are two possibilities for not seeing what you want to see once you have MAMP turned on. One possibility is that you already have "Web Sharing" turned on in your Sharing Preference Pane. If that is the case, port 80 will already be taken and you'll be seeing the default Apache install (files are stored at /Library/WebServer/Documents/). This would push MAMP to either not turn on it's web serving capabilities, or to push it to another port. The other possibility is that MAMP defaults to another port anyway. So instead of localhost, you might have to type in localhost:8080 or something similar. I believe the control panel that gets installed can take you to the currently MAMP-served page, and it can also help you change which port your serving on.
80 is the default port for web serving and the ONLY port that will let you get straight to the server without having to type in webaddress.com:port# instead of just webaddress.com.

Distributed cache with a backing-map as another distributed cache

Hi All,
Is it possible to create a distributed cache with a backing-map-schem with another distributed cache with local-storage disabled ?
Please let me know how to configure this type of cache.
regards
S

Hi Cameron,
I am trying to create a distributed-schem with a backing-map schem. is it possible to configure another distributed queue as a backing map scheme for a cache.
<distributed-scheme>
     <scheme-name>MyDistCache-2</scheme-name>
     <service-name> MyDistCacheService-2</service-name>
     <backing-map-scheme>
               <external-scheme>
                    <scheme-name>MyDistCache-3</scheme-name>
               </external-scheme>
     </backing-map-scheme>
</distributed-scheme>
     <distributed-scheme>
          <scheme-name>MyDistCache-3</scheme-name>
          <service-name> MyDistBackCacheService-3</service-name>
          <local-storage>false</local-storage>
     </distributed-scheme>
Please correct my understanding.
Regards
Srini

POF serialization with replicated cache?

Sorry again for the newbie question.
Can you use POF serialized objects in a replicated cache?
All of the examples show POF serialized objects being used with a partitioned cache.
If you can do this, are there any caveats involved with the "replication" cache? I assume it would have to be started using the same configuration as the "master" cache.

Thanks Rob.
So, you just start up the Coherence instance on the (or at the) replication site, using the same configuration as the "master"? (Of course with appropriate classpaths and such set correctly)

We lost our DVD with distributive of Adobe Photoshop CS3 ( redacted by mod-kglad , 8 license).

We lost our DVD with distributive of Adobe Photoshop CS3 (<partial license number redacted by mod - kglad>). What can we do for get new one (DVD) or can yousuggest another way for install programme (exclude buying new version like CS6)?

Thanks, but if you didn't see aboove ("the last one PC with Adobe Photshop CS3 installed in 2008 (with our serial) - chapters "Load e-License..." and "Return e-License..." was not active (in Menu "Help")",look at the screenshoot ("ps cs3>click help>...") from this PC:
As you see, there are no any "deactivate" (in Russian it means "Деактивировать") there.
Read the following answers from http://www.adobe.com/support/chat/ivrchat.html, please. It was on 25 oct 2013:
You are now chatting with Vijay Kanna .
Vijay Kanna : Hello! Welcome to Adobe Customer Service.
Vijay Kanna : Hi Ilia.
Vijay Kanna : Please allow me a moment while I review your request.
Ilia: Hello! Ok, I'm waiting.
Vijay Kanna : I have read your request.
Vijay Kanna : I will be glad to help you with the information.
Vijay Kanna : I would first like to inform you that this application you have is a Volume Licensing Product for CS3 for which its not possible to make changes on the license activation seats.
Vijay Kanna : Usually the Volume Licensing Product will not provide such error as this type of error will only show up with retail (single) user application.
Vijay Kanna : If you use the correct download link from the licensing account for this particular application or the CDs for this particular application you will not get such errors.
Ilia: Ok. Where I can download distributive of CS3 (we lost our box with CD or DVD)?
Vijay Kanna : If the CDs are lost and you have not purchased the application as a download then its not possible to find the download link for this application now as the current shipping version with Adobe is CS6.
Vijay Kanna : Adobe at the moment only has the CDs and download link for CS6.
Ilia: It means that we couldn't install our CS3 on new PC? What can we do in this case?
Vijay Kanna : You will have to locate the original CDs or your next option is to purchase the current version which is CS6.
Vijay Kanna : Also the CS3 is not compatible on Windows 7 or any other latest OS.
Vijay Kanna : Is there anything else I can help you with?
Ilia: Yes? wait a momemt please/ I consult with my boss/
Vijay Kanna : Okay.
Vijay Kanna : Are we still connected?
Ilia: Yes
Vijay Kanna : Okay.
Vijay Kanna : Do you have any further questions for me today?
Ilia: Yes, wait a moment.
Vijay Kanna : Sure. I will stay online.
Ilia: My colleague claims that a distribution kit with which we install the program on new PC is copied from lost CD.
Vijay Kanna : Ilia, the application is not installed this way. Also this error which you say "exceeded allowable activation" is not for a Volume Licensing Product and such error is only associated with the single user application.
Vijay Kanna : Hence, the installation file you have should be incorrect and for a single user application.
Ilia: Ok, thanks. We will try to find CD. Good-bye.
Vijay Kanna : You are welcome.
Vijay Kanna : Please click again to check with us, if we can be of further help.
Vijay Kanna : We will be glad to check and help you.
Vijay Kanna : Thank you for chatting. Goodbye.
Chat InformationThis chat session has ended.
Thank you for contacting Adobe."
PS: Finaly, we lost our CD or DVD (with box), we have only serial number and bild (was purhased 2008), nothing else. I tried to finding the same as we lost distributive via Google, etc a lot of time, but trere is no success.

I get my iPhone 5 from UAE AND no one inform me that no FaceTime there and I am living in lebanon I am lebanese so who will except my iPhone 5 here in Lebanon with out FaceTime I lost my money in this and Mac should replace our iPhone pls

I get my iPhone 5 from UAE AND no one inform me that no FaceTime there and I am living in lebanon I am lebanese so who will except my iPhone 5 here in Lebanon with out FaceTime I lost my money in this and Mac should replace our iPhone pls

Why you bought from the UAE .
The phone has NO international warranty and its the UAE and Saudia Arabian authorities that have instructed the function (facetime) to be removed not Apple.
Your best option is to return it to Dubai when next there.
OR contact these companies and see if you can trade to a Facetime friendly model from Europe
http://3gleb.com/pages/home.aspx
http://www.iphonelebanon.org

Concurrency with Entry Processors on Replicated Cache

Hi,
In the documentation is says that entry processors in replicated caches are executed on the initiating node.
How is concurrency handled in this situation?
What happens if two or more nodes are asked to execute something on an entry at the same time?
What happens if the node initiating the execution is a storage disabled node?
Thanks!

Jonathan.Knight wrote:
In a distributed cache the entry processor runs on the node that owns the cache entry. In a replicated cache the same entries are on all nodes so I think one of the questions was what happens in this scenario. I presume the EP only execues on one of the nodes - it would not make sense for it to execute on all nodes - but which one does it use? Is there still a concept of owner for a replicated cache or is it random.
At this point I would have coded a quick experiment to prove what happens but unfortunately I am a tad busy right now.
JKHi Jonathan,
in the replicated cache there is still a notion of ownership of an entry, in Coherence terms it is called a lease. It is always owned by the last node to have carried out a successful modification on it, where modification may be a put/remove but it can also be a lock operation. Lease granularity is per entry.
Practically the lock operation in the code Dimitri pasted serves two purposes. First it ensures no other nodes can lock it, second it brings the lease to the locking node, so it can correctly execute the entry-processor locally on the entry.
Best regards,
Robert

I have three different ipods with music on them and have had to replace our computer as it was in a fire. How can we combine the ipods into one ipod.

We had to replace our computer due to a fire and lost many of the fiels which were on them. Many were music files for the ipods, we have thre. Also, do not have ID's and passwords to the iTunes store.
How can we combine the information so that they are all in each one or at least compbine everything into one ipod?

Just so you know the method suggested by Nelsonleee will cost your $29.95 USD, Yamipod is free.

Read-Through Caching with expiry-delay and near cache (front scheme)

We are experiencing a problem with our custom CacheLoader and near cache together with expiry-delay on the backing map scheme.
I was under the assumption that it was possible to have an expiry-delay configured on the backing-scheme and that the near cache object was evicted when backing object was evicted. But according to our tests we have to put an expiry-delay on the front scheme too.
Is my assumption correct that there will not be automatic eviction on the near cache (front scheme)?
With this config, near cache is never cleared:
             <near-scheme>
                  <scheme-name>config-part</scheme-name>
                  <front-scheme>
                        <local-scheme />
                  </front-scheme>
                  <back-scheme>
                        <distributed-scheme>
                              <scheme-ref>config-part-distributed</scheme-ref>
                        </distributed-scheme>
                  </back-scheme>
            <autostart>true</autostart>
            </near-scheme>
            <distributed-scheme>
                  <scheme-name>config-part-distributed</scheme-name>
                  <service-name>partDistributedCacheService</service-name>
                  <thread-count>10</thread-count>
                  <backing-map-scheme>
                        <read-write-backing-map-scheme>
                              <read-only>true</read-only>
                              <scheme-name>partStatusScheme</scheme-name>
                              <internal-cache-scheme>
                                    <local-scheme>
                                          <scheme-name>part-eviction</scheme-name>
                                          <expiry-delay>30s</expiry-delay>
                                    </local-scheme>
                              </internal-cache-scheme>
                              <cachestore-scheme>
                                    <class-scheme>
                                          <class-name>net.jakeri.test.PingCacheLoader</class-name>
                                    </class-scheme>
                              </cachestore-scheme>
                              <refresh-ahead-factor>0.5</refresh-ahead-factor>
                        </read-write-backing-map-scheme>
                  </backing-map-scheme>
                  <autostart>true</autostart>
                  <local-storage system-property="tangosol.coherence.config.distributed.localstorage">true</local-storage>
            </distributed-scheme>With this config (added expiry-delay on front-scheme), near cache gets cleared.
        <near-scheme>
                  <scheme-name>config-part</scheme-name>
                  <front-scheme>
                        <local-scheme>
                             <expiry-delay>15s</expiry-delay>
                        </local-scheme>
                  </front-scheme>
                  <back-scheme>
                        <distributed-scheme>
                              <scheme-ref>config-part-distributed</scheme-ref>
                        </distributed-scheme>
                  </back-scheme>
            <autostart>true</autostart>
            </near-scheme>
            <distributed-scheme>
                  <scheme-name>config-part-distributed</scheme-name>
                  <service-name>partDistributedCacheService</service-name>
                  <thread-count>10</thread-count>
                  <backing-map-scheme>
                        <read-write-backing-map-scheme>
                              <read-only>true</read-only>
                              <scheme-name>partStatusScheme</scheme-name>
                              <internal-cache-scheme>
                                    <local-scheme>
                                          <scheme-name>part-eviction</scheme-name>
                                          <expiry-delay>30s</expiry-delay>
                                    </local-scheme>
                              </internal-cache-scheme>
                              <cachestore-scheme>
                                    <class-scheme>
                                          <class-name>net.jakeri.test.PingCacheLoader</class-name>
                                    </class-scheme>
                              </cachestore-scheme>
                              <refresh-ahead-factor>0.5</refresh-ahead-factor>
                        </read-write-backing-map-scheme>
                  </backing-map-scheme>
                  <autostart>true</autostart>
                  <local-storage system-property="tangosol.coherence.config.distributed.localstorage">true</local-storage>
            </distributed-scheme>

Hi Jakkke,
The Near Cache scheme allows to have configurable levels of cache coherency from the most basic expiry based cache to invalidation based cache to data versioning cache depending on the coherency requirements. The Near Cache is commonly used to achieve the performance of replicated cache without losing the scalability aspects of replicated cache and this is achieved by having a subset of data (based on MRU or MFU) in the <front-scheme> of the near cache and the complete set of data in the <back-scheme> of near cache. The <back-scheme> updates can automatically trigger events to invalidate the entries in the <front-scheme> based on the invalidation strategy (present, all, none, auto) configured for the near cache.
If you want to expire the entries in the <front-scheme> and <back-scheme>, you need to specify an expiry-delay on both the schemes as mentioned by you in the last example. Now if you are expiring the items in the <back-scheme> for the reason that they get loaded again from the cache-store but the <front-scheme> keys remain same (only the values should be refreshed from the cache store) then you need not set the expiry-delay on the <front-scheme> rather mention the invalidation-strategy as present. But if you want to have a different set of entries in <front-scheme> after a specified expiry delay then you need to mention it in the <front-scheme> configuration.
The near cache has the capability to keep front scheme and back scheme data in sync but the expiry of entries is not synced. Always, front-scheme is a subset of back-scheme.
Hope this helps!
Cheers,
NJ

Error while putting an object in Replicated Cache

Hi,
I am running just a single node of coherence with Replicated cache. But when I am trying to add an object to it I am getting the below exception. However I don't get this error while doing the same thing in a Distributed cache. Can someone please tell me what could I be doing wrong here.
Caused by: java.io.IOException: readObject failed: java.lang.ClassNotFoundException: com.test.abc.pkg.RRSCachedObject
     at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
     at java.security.AccessController.doPrivileged(Native Method)
     at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
     at java.lang.ClassLoader.loadClass(ClassLoader.java:316)
     at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
     at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:374)
     at java.lang.Class.forName0(Native Method)
     at java.lang.Class.forName(Class.java:242)
     at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:585)
     at com.tangosol.io.ResolvingObjectInputStream.resolveClass(ResolvingObjectInputStream.java:68)
     at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1544)
     at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1466)
     at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1699)
     at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1305)
     at java.io.ObjectInputStream.readObject(ObjectInputStream.java:348)
     at com.tangosol.util.ExternalizableHelper.readSerializable(ExternalizableHelper.java:2145)
     at com.tangosol.util.ExternalizableHelper.readObjectInternal(ExternalizableHelper.java:2276)
     at com.tangosol.util.ExternalizableHelper.deserializeInternal(ExternalizableHelper.java:2673)
     at com.tangosol.util.ExternalizableHelper.fromBinary(ExternalizableHelper.java:257)
     at com.tangosol.coherence.component.net.extend.proxy.CacheServiceProxy$ConverterFromBinary.convert(CacheServiceProxy.CDB:4)
     at com.tangosol.util.ConverterCollections$ConverterCacheMap.put(ConverterCollections.java:2433)
     at com.tangosol.coherence.component.util.collections.wrapperMap.WrapperNamedCache.put(WrapperNamedCache.CDB:1)
     at com.tangosol.coherence.component.net.extend.proxy.CacheServiceProxy$WrapperNamedCache.put(CacheServiceProxy.CDB:2)
     at com.tangosol.coherence.component.net.extend.messageFactory.NamedCacheFactory$PutRequest.onRun(NamedCacheFactory.CDB:6)
     at com.tangosol.coherence.component.net.extend.message.Request.run(Request.CDB:4)
     at com.tangosol.coherence.component.net.extend.proxy.NamedCacheProxy.onMessage(NamedCacheProxy.CDB:11)
     at com.tangosol.coherence.component.net.extend.Channel.execute(Channel.CDB:28)
     at com.tangosol.coherence.component.net.extend.Channel.receive(Channel.CDB:26)
     at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Peer$DaemonPool$WrapperTask.run(Peer.CDB:9)
     at com.tangosol.coherence.component.util.DaemonPool$WrapperTask.run(DaemonPool.CDB:32)
     at com.tangosol.coherence.component.util.DaemonPool$Daemon.onNotify(DaemonPool.CDB:69)
     at com.tangosol.coherence.component.util.Daemon.run(Daemon.CDB:42)
     at java.lang.Thread.run(Thread.java:613)
ClassLoader: java.net.URLClassLoader@b5f53a
     at com.tangosol.util.ExternalizableHelper.fromBinary(ExternalizableHelper.java:261)
     at com.tangosol.coherence.component.net.extend.proxy.CacheServiceProxy$ConverterFromBinary.convert(CacheServiceProxy.CDB:4)
     at com.tangosol.util.ConverterCollections$ConverterCacheMap.put(ConverterCollections.java:2433)
     at com.tangosol.coherence.component.util.collections.wrapperMap.WrapperNamedCache.put(WrapperNamedCache.CDB:1)
     at com.tangosol.coherence.component.net.extend.proxy.CacheServiceProxy$WrapperNamedCache.put(CacheServiceProxy.CDB:2)
     at com.tangosol.coherence.component.net.extend.messageFactory.NamedCacheFactory$PutRequest.onRun(NamedCacheFactory.CDB:6)
     at com.tangosol.coherence.component.net.extend.message.Request.run(Request.CDB:4)
     at com.tangosol.coherence.component.net.extend.proxy.NamedCacheProxy.onMessage(NamedCacheProxy.CDB:11)
     at com.tangosol.coherence.component.net.extend.Channel.execute(Channel.CDB:28)
     at com.tangosol.coherence.component.net.extend.Channel.receive(Channel.CDB:26)
     at com.tangosol.coherence.component.util.daemon.queueProcessor.service.Peer$DaemonPool$WrapperTask.run(Peer.CDB:9)
     at com.tangosol.coherence.component.util.DaemonPool$WrapperTask.run(DaemonPool.CDB:32)
     at com.tangosol.coherence.component.util.DaemonPool$Daemon.onNotify(DaemonPool.CDB:69)
     at com.tangosol.coherence.component.util.Daemon.run(Daemon.CDB:42)
     at java.lang.Thread.run(Thread.java:613)
This is my config file -
<cache-config>
     <caching-scheme-mapping>
          <cache-mapping>
               <cache-name>*</cache-name>
               <scheme-name>MY-replicated-cache-scheme</scheme-name>
          </cache-mapping>
     </caching-scheme-mapping>
     <caching-schemes>
          
          <replicated-scheme>
               <scheme-name>MY-replicated-cache-scheme</scheme-name>
               <service-name>ReplicatedCache</service-name>
               <backing-map-scheme>
                    <local-scheme>
                    </local-scheme>
               </backing-map-scheme>
               <lease-granularity>member</lease-granularity>
               <autostart>true</autostart>
          </replicated-scheme>
          <proxy-scheme>
               <service-name>ExtendTcpProxyService</service-name>
               <thread-count>5</thread-count>
               <acceptor-config>
                    <tcp-acceptor>
                         <local-address>
                              <address>server</address>
                              <port>port</port>
                         </local-address>
                         <receive-buffer-size>768k</receive-buffer-size>
                         <send-buffer-size>768k</send-buffer-size>
                    </tcp-acceptor>
               </acceptor-config>
               <autostart>true</autostart>
          </proxy-scheme>
     </caching-schemes>
</cache-config>
Edited by: user1945969 on Jun 5, 2010 4:16 PM

By default, it should have used FIXED as unit-calculator. But look at the trace seems your replicated cache was using BINARY as unit-calculator.
Could you try add <unit-calculator>FIXED</unit-calculator> in your cache config for the replicate cache.
Or just try insert a object (both key and value) which implement Binary.
Check the unit-calculator part on this link
http://wiki.tangosol.com/display/COH35UG/local-scheme

Replacing our Replicated Caches with Distributed+CQC

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