If there is single database handing out the Identifiers, then does it matter whether there are concurrent callers from multiple or single JVM?
Michael Vorburger-4 wrote: > > Sorry I meant clustering of JVM/AppServers, not databases. > > Can you or somebody else comment on that? - Maybe my question is actually > stupid, and all works well as is... Each JVM node will get a separate > "block" of IDs from e.g. OPENJPA_SEQUENCE_TABLE, and OpenJPA handles some > form of locking/retry on that table to avoid hypothetical collision? All > is well, out of the box? Hm... would love somebody to confirm (or deny) > this... > > Thanks a lot. > > > -----Original Message----- > From: Pinaki Poddar [mailto:[EMAIL PROTECTED] > Sent: jeudi, 10. juillet 2008 04:24 > To: [email protected] > Subject: Re: Clustering & ID TableGenerator (OPENJPA_SEQUENCE_TABLE) > > > Are you referring to clustering of databases or clustering of > JVM/AppServers? > If it is the former, openjpa-slice module that let a persistent unit be > connected to multiple databases in the same transaction may be of some > relevance. In slice, we designate one database in the cluster as 'master' > for the purpose of ID generation. > > > Michael Vorburger-4 wrote: >> >> Hello, >> >> How do you do Clustering and ID TableGenerator >> (e.g.OPENJPA_SEQUENCE_TABLE) ? >> >> Will this somehow magically work (how?), or will different nodes "step >> on each other's feet" because they'll use the same PK? Can they each >> use different "slices" ? >> >> If impossible, do you HAVE to use Identify columns or Sequence >> generators in the DB? I thought that was not such a good idea (if you >> have a choice), performance wise, because it requires an extra >> round-trip to the DB to get the PK e.g. to set it as FK. Also >> https://issues.apache.org/jira/browse/OPENJPA-464 states that >> Statement Batching won't work with GeneratedType=IDENTITY - so this >> option doesn't seem terribly tempting in order to get ID and >> clustering happily married together. >> >> How do people out there do this with OpenJPA? >> >> Thank you, >> Michael >> >> _____________________________ >> Michael Vorburger, Odyssey Financial Technologies >> >> >> ____________________________________________________________ >> >> This email and any files transmitted with it are CONFIDENTIAL and >> intended >> solely for the use of the individual or entity to which they are >> addressed. >> Any unauthorized copying, disclosure, or distribution of the >> material within >> this email is strictly forbidden. >> Any views or opinions presented within this e-mail are solely those >> of the >> author and do not necessarily represent those of Odyssey Financial >> Technologies SA unless otherwise specifically stated. >> An electronic message is not binding on its sender. Any message >> referring to >> a binding engagement must be confirmed in writing and duly signed. >> If you have received this email in error, please notify the sender >> immediately >> and delete the original. >> > > -- > View this message in context: > http://n2.nabble.com/Clustering---ID-TableGenerator-%28OPENJPA_SEQUENCE_TABLE%29-tp471147p471566.html > Sent from the OpenJPA Users mailing list archive at Nabble.com. > > > ____________________________________________________________ > > This email and any files transmitted with it are CONFIDENTIAL and > intended > solely for the use of the individual or entity to which they are > addressed. > Any unauthorized copying, disclosure, or distribution of the material > within > this email is strictly forbidden. > Any views or opinions presented within this e-mail are solely those of > the > author and do not necessarily represent those of Odyssey Financial > Technologies SA unless otherwise specifically stated. > An electronic message is not binding on its sender. Any message > referring to > a binding engagement must be confirmed in writing and duly signed. > If you have received this email in error, please notify the sender > immediately > and delete the original. > > -- View this message in context: http://n2.nabble.com/Clustering---ID-TableGenerator-%28OPENJPA_SEQUENCE_TABLE%29-tp471147p472570.html Sent from the OpenJPA Users mailing list archive at Nabble.com.
