If the object is in the same transaction, the exisiting object will be returned. If the object is in the cache, but not in the same transaction, a java object is instantiated using the cached values. If not, object is instantiated and value is loaded from the database.
Thomas -----Original Message----- >From: Matthew Baird [mailto:[EMAIL PROTECTED]] >Sent: Friday, January 04, 2002 4:16 PM >To: [EMAIL PROTECTED] >Subject: Re: [castor-dev] Does caching improve read performance? > >does the OQL query re construct the objects from the database, or just >look them up based on identity and build them only if needed? > >-----Original Message----- >From: Thomas Yip [mailto:[EMAIL PROTECTED]] >Sent: Friday, January 04, 2002 4:11 PM >To: [EMAIL PROTECTED] >Subject: Re: [castor-dev] Does caching improve read performance? > > > >OQLQuery always goes to the database, because there is no easy way to >tell >if all rows interested visible to current transaction are already in >cache. > >For simply data object model, which has no relationship, it is expected >to >have similar timing. > > > >Thomas > >-----Original Message----- >>From: Jackson, Scott M [mailto:[EMAIL PROTECTED]] >>Sent: Wednesday, January 02, 2002 6:36 PM >>To: [EMAIL PROTECTED] >>Subject: [castor-dev] Does caching improve read performance? >> >>Hello , >> >>>From what I have been able to read, if castor does an oqlquery on an >object >>(thereby caching it from the database), the next time a similar read is >done >>should be from the cache, thereby significantly enhancing read >performance. >>I have benchmarked multiple SELECTs on the same object with both >>cache-type="none" and cache-type="unlimited" (10 of each in succession) >and >>got identical timings. Watching the database logs, I saw the same >selects >>were performed for each and every query. It appears that no caching is >>occurring. These 10 SELECTs are done in independent transactions (and >with >>new JDO's) and with a new DataBase object for every query as >recommended to >>avoid concurrency issues. The server of course is up for the all the >>transactions. Am I doing it wrong or what am I missing? >> >> >>Thank you, >> >>Scott Jackson >> >>p.s. I tried it with a single instantiation of jdo with the same result >>(timing is identical -- a little faster for both sets though). >> >>----------------------------------------------------------- >>If you wish to unsubscribe from this mailing, send mail to >>[EMAIL PROTECTED] with a subject of: >> unsubscribe castor-dev >> > >----------------------------------------------------------- >If you wish to unsubscribe from this mailing, send mail to >[EMAIL PROTECTED] with a subject of: > unsubscribe castor-dev > >----------------------------------------------------------- >If you wish to unsubscribe from this mailing, send mail to >[EMAIL PROTECTED] with a subject of: > unsubscribe castor-dev > ----------------------------------------------------------- If you wish to unsubscribe from this mailing, send mail to [EMAIL PROTECTED] with a subject of: unsubscribe castor-dev
