Re: Cache Issue in distributed environment
Hi Cedric, Cédric Talon wrote: Hi, I am new on this mailing list and so it is my first message. welcome to this list! I am working on a project which is using OJB in a distributed environment. The distributed issue is my problem ! I have read there are important points to respect in this case. The first one is to use Sequence Manager. It's ok for me. The second one is the locking issue. I am using the LockManagerRemoteImpl. So I think it is ok. Do you use the ODMG-api implementation? http://db.apache.org/ojb/docu/guides/odmg-guide.html Only this implementation supports pessimistic locking by default. The PB-api http://db.apache.org/ojb/docu/guides/pb-guide.html only supports optimistic locking by default. http://db.apache.org/ojb/docu/guides/lockmanager.html For best performance I would recommend to use optimistic locking (needs a 'version' column in the database table) for all concurrent modified persistence objects. The last point is the cache issue. And this is the subject of this mail. Currently I am using ObjectCacheDefaultImpl. I know it is not suitable for distributed environment. That's why I'd like to use distributed cache. Here you can find a short description how the cache works http://www.mail-archive.com/ojb-user@db.apache.org/msg16075.html My estimation is that in most cases OJB will benefit more from a fast DB/DB-cache/network (in combination with a session cache) than from a distributed cache (except you do a lot of get object by identity stuff). I would recommend to run some load tests with/without distributed cache. I have heard about OS Cache but it requires a multicast network. It is not possible in my case. I have heard about JCS too. Has anybody ever used it? Sorry, I don't have experience in this. I don't find information to configure it with OJB. Can anybody help me ? If you use OJB 1.0.5rc1 change the object-cache element within your jdbc-connection-descriptor to one global cache region: object-cache class=JCS /object-cache a cache region for each class: object-cache class=JCSPerClass /object-cache For version 1.0.4 specifiy the full qualified class name (e.g. org.apache.ojb.broker.cache.ObjectCacheJCSPerClassImpl). You can configure the JCS cache via the cache.ccf properties file. regards, Armin - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Cache Issue in distributed environment
Armin Waibel wrote: I don't find information to configure it with OJB. Can anybody help me ? If you use OJB 1.0.5rc1 change the object-cache element within your jdbc-connection-descriptor to one global cache region: object-cache class=JCS /object-cache a cache region for each class: object-cache class=JCSPerClass /object-cache For version 1.0.4 specifiy the full qualified class name (e.g. org.apache.ojb.broker.cache.ObjectCacheJCSPerClassImpl). You can configure the JCS cache via the cache.ccf properties file. Sorry, I have to clarify my last post. I would recommend to use the two level cache with the distributed cache as second level cache. If you use OJB 1.0.5rc1: object-cache class=twoLevel !-- ObjectCacheTwoLevelImpl attributes -- attribute attribute-name=applicationCache attribute-value=jcs/ attribute attribute-name=copyStrategy attribute-value=default/ attribute attribute-name=forceProxies attribute-value=false/ /object-cache OJB 1.0.4: object-cache class=org.apache.ojb.broker.cache.ObjectCacheTwoLevelImpl !-- ObjectCacheTwoLevelImpl attributes -- attribute attribute-name=applicationCache attribute-value=org.apache.ojb.broker.cache.ObjectCacheJCSImpl/ attribute attribute-name=copyStrategy attribute-value=org.apache.ojb.broker.cache.ObjectCacheTwoLevelImpl$CopyStrategyImpl/ attribute attribute-name=forceProxies attribute-value=false/ /object-cache regards, Armin - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Cache Issue in distributed environment
Hi, I am new on this mailing list and so it is my first message. I am working on a project which is using OJB in a distributed environment. The distributed issue is my problem ! I have read there are important points to respect in this case. The first one is to use Sequence Manager. It's ok for me. The second one is the locking issue. I am using the LockManagerRemoteImpl. So I think it is ok. The last point is the cache issue. And this is the subject of this mail. Currently I am using ObjectCacheDefaultImpl. I know it is not suitable for distributed environment. That's why I'd like to use distributed cache. I have heard about OS Cache but it requires a multicast network. It is not possible in my case. I have heard about JCS too. Has anybody ever used it? I don't find information to configure it with OJB. Can anybody help me ? Regards Cedric TALON
Clear cache issue!
Hi All, I'm using the following code: QueryByCriteria queryByCriteria = new QueryByCriteria(RefInfoData.class, criteria, true); broker.clearCache(); Collection refInfo = (Collection) broker.getCollectionByQuery(queryByCriteria); For the class 'RefInfoData' we have set the cache level as default implementation. When we use the method broker.clearCache() we are facing performance issues. But when we don't clear cache there is dirty read. We are maintaining the cache for reference tables. Is there a way to clear cache for the specific object instead of whole cache? Regards, Vagula CAUTION - Disclaimer * This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely for the use of the addressee(s). If you are not the intended recipient, please notify the sender by e-mail and delete the original message. Further, you are not to copy, disclose, or distribute this e-mail or its contents to any other person and any such actions are unlawful. This e-mail may contain viruses. Infosys has taken every reasonable precaution to minimize this risk, but is not liable for any damage you may sustain as a result of any virus in this e-mail. You should carry out your own virus checks before opening the e-mail or attachment. Infosys reserves the right to monitor and review the content of all messages sent to or from this e-mail address. Messages sent to or from this e-mail address may be stored on the Infosys e-mail system. ***INFOSYS End of Disclaimer INFOSYS***
Re: Clear cache issue!
Hi Vagula, Consider this one: broker.removeFromCache(entityOrId); Cheers, Vasily On 10/16/06, Vagula [EMAIL PROTECTED] wrote: Hi All, I'm using the following code: QueryByCriteria queryByCriteria = new QueryByCriteria(RefInfoData.class, criteria, true); broker.clearCache(); Collection refInfo = (Collection) broker.getCollectionByQuery(queryByCriteria); For the class 'RefInfoData' we have set the cache level as default implementation. When we use the method broker.clearCache() we are facing performance issues. But when we don't clear cache there is dirty read. We are maintaining the cache for reference tables. Is there a way to clear cache for the specific object instead of whole cache? Regards, Vagula CAUTION - Disclaimer * This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely for the use of the addressee(s). If you are not the intended recipient, please notify the sender by e-mail and delete the original message. Further, you are not to copy, disclose, or distribute this e-mail or its contents to any other person and any such actions are unlawful. This e-mail may contain viruses. Infosys has taken every reasonable precaution to minimize this risk, but is not liable for any damage you may sustain as a result of any virus in this e-mail. You should carry out your own virus checks before opening the e-mail or attachment. Infosys reserves the right to monitor and review the content of all messages sent to or from this e-mail address. Messages sent to or from this e-mail address may be stored on the Infosys e-mail system. ***INFOSYS End of Disclaimer INFOSYS*** - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: Clear cache issue!
Hi, I tried this: broker.removeFromCache(entityOrId); But this also results in dirty read. Regards, Vagula -Original Message- From: Vasily Ivanov [mailto:[EMAIL PROTECTED] Sent: Monday, October 16, 2006 12:51 PM To: OJB Users List Subject: Re: Clear cache issue! Hi Vagula, Consider this one: broker.removeFromCache(entityOrId); Cheers, Vasily On 10/16/06, Vagula [EMAIL PROTECTED] wrote: Hi All, I'm using the following code: QueryByCriteria queryByCriteria = new QueryByCriteria(RefInfoData.class, criteria, true); broker.clearCache(); Collection refInfo = (Collection) broker.getCollectionByQuery(queryByCriteria); For the class 'RefInfoData' we have set the cache level as default implementation. When we use the method broker.clearCache() we are facing performance issues. But when we don't clear cache there is dirty read. We are maintaining the cache for reference tables. Is there a way to clear cache for the specific object instead of whole cache? Regards, Vagula CAUTION - Disclaimer * This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely for the use of the addressee(s). If you are not the intended recipient, please notify the sender by e-mail and delete the original message. Further, you are not to copy, disclose, or distribute this e-mail or its contents to any other person and any such actions are unlawful. This e-mail may contain viruses. Infosys has taken every reasonable precaution to minimize this risk, but is not liable for any damage you may sustain as a result of any virus in this e-mail. You should carry out your own virus checks before opening the e-mail or attachment. Infosys reserves the right to monitor and review the content of all messages sent to or from this e-mail address. Messages sent to or from this e-mail address may be stored on the Infosys e-mail system. ***INFOSYS End of Disclaimer INFOSYS*** - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Cache issue
Hi Tino, I don't think that OJB is the problem (but maybe I'm wrong). The only difference between the Criteria is the 'distinct' flag. So I this Access has a problem with the distinct flag. Please enable p6spy to trace the generated SQL statements. See http://db.apache.org/ojb/faq.html#How can I trace and/or profile SQL statements executed by OJB? How does the generated SQL for both Criteria look like? Try to invoke these statements against your DB and compare the results. If both statements return the same result ... OJB has a problem ;-) regards, Armin Tino Schöllhorn wrote: Hello Armin, I could pinpoint the described error. It all boils to the QueryFactory.newQuery(Class, Criteria, boolean) method. if I execute the code to retrieve an instance of class Person with: Criteria crit = new Criteria(); crit.addEqualTo(id, 85); Query query = QueryFactory.newQuery(Person.class, crit); Collection c = pb.getCollectionByQuery(query); and so on everything works perfectly and the instances of Person are instantiated correctly. But if I use the method described in the first place: Criteria crit = new Criteria(); crit.addEqualTo(id, 85); Query query = QueryFactory.newQuery(Person.class, crit, true); After that query the LONGVARCHARS aren't correctly instantiated. I think that this might be an error of OJB. With regards Tino Armin Waibel wrote: Hi, Tino Schöllhorn wrote: Hi, I have (again) something weird which I suppose is just a configuration problem: I have a class Person which has one LONGVARCHAR-Field. The first time the object is accessed the LONGVARCHAR-field is returned correctly. hmm, does this mean first time after creation? Which cache was used? Maybe first time after store it was found in cache, second time it was read from DB. So I assume your database truncate the String on insert. Maybe I'm wrong ;-) regards, Armin But the second time it is accessed it returns just 256 (I suppose) characters. I am using Access as 'database' but I don't think this is the problem. Do you have any ideas what I could try? Tino - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Cache issue
Hi, Tino Schöllhorn wrote: Hi, I have (again) something weird which I suppose is just a configuration problem: I have a class Person which has one LONGVARCHAR-Field. The first time the object is accessed the LONGVARCHAR-field is returned correctly. hmm, does this mean first time after creation? Which cache was used? Maybe first time after store it was found in cache, second time it was read from DB. So I assume your database truncate the String on insert. Maybe I'm wrong ;-) regards, Armin But the second time it is accessed it returns just 256 (I suppose) characters. I am using Access as 'database' but I don't think this is the problem. Do you have any ideas what I could try? Tino - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Cache issue
Hello Armin, I could pinpoint the described error. It all boils to the QueryFactory.newQuery(Class, Criteria, boolean) method. if I execute the code to retrieve an instance of class Person with: Criteria crit = new Criteria(); crit.addEqualTo(id, 85); Query query = QueryFactory.newQuery(Person.class, crit); Collection c = pb.getCollectionByQuery(query); and so on everything works perfectly and the instances of Person are instantiated correctly. But if I use the method described in the first place: Criteria crit = new Criteria(); crit.addEqualTo(id, 85); Query query = QueryFactory.newQuery(Person.class, crit, true); After that query the LONGVARCHARS aren't correctly instantiated. I think that this might be an error of OJB. With regards Tino Armin Waibel wrote: Hi, Tino Schöllhorn wrote: Hi, I have (again) something weird which I suppose is just a configuration problem: I have a class Person which has one LONGVARCHAR-Field. The first time the object is accessed the LONGVARCHAR-field is returned correctly. hmm, does this mean first time after creation? Which cache was used? Maybe first time after store it was found in cache, second time it was read from DB. So I assume your database truncate the String on insert. Maybe I'm wrong ;-) regards, Armin But the second time it is accessed it returns just 256 (I suppose) characters. I am using Access as 'database' but I don't think this is the problem. Do you have any ideas what I could try? Tino - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
