HHH-9993 - IsolationDelegate + no-Connection
by Steve Ebersole
HHH-9993[1] is a request to extend IsolationDelegate to cater for
transaction hooks which do not need access to a JDBC Connection.
A quick primer for those unfamiliar, IsolationDelegate is a contract to
allow work to be done in a fashion that makes sure it is isolated from the
main Session transaction. We have implementations of this to fit JTA and
JDBC scenarios. Additionally, it allows to indicate that the isolated work
should itself be transacted or not. In the JDBC-transaction scenario
(which HHH-9993 deals with) transacted-isolated work is achieved by passing
in a separate Connection to use since that is the only way to achieve a new
transaction in JDBC (JDBC has no "suspend/resume" transaction
functionality).
HHH-9993 is again about this isolated, transacted scenario under the
JDBC-transaction handling. Specifically for hibernate-infinispan call
backs there is no need to obtain the second Connection. So HHH-9993 is
about reducing the overhead of this call by allowing it a way to say "I
need to do some isolated, transacted work but I do not need the Connection".
For this particular use case that is fine: hibernate-infinispan will never
access the Connection. I do worry however about this general use-case. My
concern is specifically that some use cases will attempt to call back into
the Session. At the moment we do not "protect" against that.
I'd like to get some opinions on this.
[1] https://hibernate.atlassian.net/browse/HHH-9993
9 years, 10 months
Statements issued for unidirectional one-to-many with @JoinColumn
by Gunnar Morling
Steve, all,
I have a model with two entities, Parent and Child, and an
unidirectional one-to-many association from the former to the latter.
Via @JoinColumn on the association it is ensured that the Parent FK is
stored in the Child table, i.e. without a separate join table. When
inserting a Parent and several Child entities, I see the following
statements:
INSERT INTO parent (id, name) VALUES (?,?)
INSERT INTO child (id, childname) VALUES (?,?)
INSERT INTO child (id, childname) values (?,?)
UPDATE CHILD SET Parent_id=? WHERE id=?
UPDATE CHILD SET Parent_id=? WHERE id=?
Why is it that the FK is propagated through separate updates instead
of doing it as part of the Child insert?
Thanks,
--Gunnar
9 years, 10 months
[OGM] How to get the transaction id
by Davide D'Alto
Hi,
for the implementation of the Neo4j remote dialect I need to get the
identifier of the transaction.
I suppose this is something that we will need for other dialect as well in
the future.
What's the proper way to get the transaction id or the transaction? Is it
via the TransactionDriver?
Once I have the transaction id, one possible solution is to pass it to the
method of the GridDialect interface using an addtional parameter,
TransactionContext, that could contain information about the running
transaction.
Thanks,
Davide
9 years, 10 months
hbm mapping files and EntityManager
by Gail Badner
By default, hbm mapping files are detected when building Hibernate
EntityManager.
Is that expected?
I see that it is possible to override this behavior by setting
hibernate.archive.autodetection="".
I was surprised by the default. I would have thought that an application
using EntityManager would need to explicitly opt-in to use hbm files.
Thanks,
Gail
9 years, 10 months
Forum database banned emails issue
by Vlad Mihalcea
Hi,
I tried to import the last 24 hour forum spam emails form
https://www.stopforumspam.com/, which is around 50k email entries.
The email were imported, but now the banned email page of the forum doesn't
load anymore.
The problem is related to how phpBB renders the page since there's a
dropdown where all emails must listed.
Could someone delete a part of those entries or give me access to the DB so
I can remove them myself?
Vlad
9 years, 10 months
Jenkins notification misfire "hibernate-orm-master-h2-infinispan8"
by Sanne Grinovero
Hello all,
today I enabled an old build job on ci.hibernate.org named
"hibernate-orm-master-h2-infinispan8" and when it failed it
automatically sent a complaint to many, many of you.
Apologies, that was not intentional but a misconfiguration of the job.
It shouldn't happen again, or if it happens it should be for good
reason like a failure of a patch you contributed, or because you're
responsible for the component's quality.
That wasn't the case today, so please ignore that single but annoying
notification.
Thanks,
Sanne
9 years, 10 months
Oracle12cDialect identity support
by Gail Badner
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
9 years, 10 months
