I think my preference would be to override in Oracle*Dialect getNativeIdentifierGeneratorClass so that it always returns SequenceStyleGenerator
1. it would be backward compatible with the logic we had for ever (with the exception of 5.0 but I understand that it is not really reliable) 2. I suppose sequences are still the preferred choices for Oracle DB DBAs. Emmanuel > On 24 Dec 2015, at 02:46, Gail Badner <gbad...@redhat.com> wrote: > > Oracle12cDialect was added in 5.0 by HHH-9044. Unfortunately there are > problems with the new identity support that Oracle12cDialect introduced > (HHH-9983). The fix for HHH-9983 involved SPI changes, so it was applied to > master for 5.1 (only). > > A couple of weeks ago, Andrea found that identities seemed to work using > 5.0 when running BulkManipulationTest using Oracle JDBC 12.1.0.1.0. At the > same time it failed for me in the same way as HHH-9983 using 12.1.0.2.0. > Then Andrea and I switched the JDBC versions (Andrea tried 12.1.0.1.0; I > tried 12.1.0.2.0) and we were both able to run BulkManipulationTest > successfully. This was very strange, especially since we were using the > same Oracle instance, each using a different user. I didn't see any > difference in how we were setting Hibernate properties. Several days later, > I tried Oracle JDBC 12.1.0.2.0 again, but BulkManipulationTest was failing > again in the same way as HHH-9983. > > Does anyone know how to get Oracle12cDialect's identity support to work for > 5.0 reliably? Is there some version of Oracle JDBC or DB configuration that > is required? > > If so, please let me know. The rest of this email assumes it is not > possible. If I'm missing some configuration detail, then just ignore the > rest of this message. > > When the unit tests are run using Oracle12cDialect on 5.0, there are many > failures: > * tests with entities explicitly mapped to use an identity fail; these > failures did not happen in 4.3 using Oracle10gDialect because these tests > where skipped (because Oracle10cDialect#supportsIdentityColumns returns > false) > * use @GeneratedValue with default strategy or use hbm mapping for ID > <generator class="native"/>; these failures did not happen in 4.3 because > the native generator for Oracle10gDialect uses a sequence; the native > generator for Oracle12cDialect uses an identity. > > Also, starting in 5.0, when using Oracle 12c, StandardDialectResolver will > automatically resolve to Oracle12cDialect if the dialect is not explicitly > mapped. Previously it would have resolved ot Oracle10gDialect. > > I would be OK with changing the native generator in 5.0 from sequence to > identity if identities were working properly. I think it will cause > confusion when applications break. To get things working with 5.0, > applications will need to explicitly set the dialect to Oracle10gDialect, > extend Oracle12cDialect to disable identity support, or change ID mappings > to specify sequences. > > Here are some alternatives to get things working. > > Alternative A: > 1) for 5.0 through 5.x override Dialect#getNativeIdentifierGeneratorClass > to return SequenceStyleGenerator.class; I suggest the change for 5.x > because I don't think it would be an acceptable to change the native > generator for Oracle12cDialect from using a sequence to using an identity > in 5.x; > 2) for 5.0 only, remove support for identities; > 3) for 6.0, if desireable, extend Oracle12gDialect (or whatever is current > at that time) to change the native generator to use an identity. > > Alternative B: > 1) for 5.0 through 5.x, leave Oracle12cDialect as is, and add a new dialect > with native generator that uses a sequence (i.e., > Oracle12cNativeSequenceGeneratorDialect or something else that is not so > ugly); > 2) for 5.0 through 5.x, change StandardDialectResolver to automatically > resolve to Oracle12cNativeSequenceGeneratorDialect for Oracle 12g server. > > Alternative C: > 1) for 5.0 through 5.x, change native generator for Oracle12cDialect to use > sequence; leave identity support as is (broken in 5.0; fixed in 5.1); > 2) for 5.0 through 5.x, add a new dialect with native generator that uses > an identity (Oracle12cNativeIdentityGeneratorDialect or something else that > is not so ugly). > 3) change StandardDialectResolver to automatically resolve to > Oracle12cDialect for Oracle 12g server. > > I prefer alternative A. Alternatives B and C involve maintaining 2 dialects > for the same Oracle version; I would think that one of them would be > deprecated moving forward. > > Thoughts? > > Thanks, > Gail > _______________________________________________ > hibernate-dev mailing list > hibernate-dev@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/hibernate-dev _______________________________________________ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
