Re: [hibernate-dev] HHH-6726 LONG and LONG RAW column types in Oracle
by Łukasz Antoniak
Currently Oracle supports database versions from 10.1 to 11.2 [1]. LONG
and LONG RAW data types are deprecated since version 8 and 8i (released
before September 2000) [2]. Oracle keeps those column types only for
backward compatibility [3].
I tried the following scenario (Oracle 10gR2):
1. Create schema with "hibernate.hbm2ddl.auto" set to "create". The LONG
column is created.
2. Insert some data.
3. Modify Oracle dialect as Gail suggested. Avoid setting
"hibernate.hbm2ddl.auto".
4. Insert some data.
To my surprise the test actually passed :). However, I think that we
cannot guaranty the proper behavior in every situation.
As for performance, ImageType is extracted by calling
ResultSet.getBytes() method, which fetches all data in one call [4]. I
don't suppose a major performance difference when data is streamed in
another call. oracle.jdbc.driver.LongRawAccessor.getBytes also fetches
data by reading the stream.
The bug reading LONG column affects JDBC drivers since version 10.2.0.4.
I think that we have to choose between:
- changing Oracle10gDialect. Make a not about it in migration guide to
4.0 and update "5.2.2. Basic value types" chapter in Hibernate
documentation.
- introducing Oracle11gDialect. It can sound weird to access Oracle 10g
database with Oracle 11g dialect.
- disabling execution of Hibernate tests that fail because of this issue
with @SkipForDialect (and maybe develop another version of them with
CLOBs and BLOBs, @RequiresDialect). Hibernate is written correctly
according to "Default Mappings Between SQL Types and Java Types"
(referenced earlier by Gail) and this is more Oracle's JDBC
implementation issue. This option came to my mind, but it's weird :P.
I would vote for the first option.
Regards,
Lukasz Antoniak
[1]
http://www.oracle.com/us/support/library/lifetime-support-technology-0691...
(page 4)
[2]
http://download.oracle.com/docs/cd/A91202_01/901_doc/server.901/a90120/ch...
[3]
http://download.oracle.com/docs/cd/B28359_01/server.111/b28318/datatype.htm
[4] "Getting a LONG RAW Data Column with getBytes"
http://download.oracle.com/docs/cd/B19306_01/java.102/b14355/jstreams.htm
Strong Liu pisze:
> I think oracle 11g is the only one supported DB version by oracle, can we just introduce a new oracle dialect with suggested changes, and deprecate all other existed oracle dialects? this won't affects users app
>
> -----------
> Strong Liu <stliu(a)hibernate.org>
> http://hibernate.org
> http://github.com/stliu
>
> On Oct 15, 2011, at 11:14 AM, Scott Marlow wrote:
>
>> How does this impact existing applications? Would they have to convert
>> LONGs to CLOBs (and LONGRAWs to BLOBs) to keep the application working?
>>
>> As far as the advantage of CLOB over TEXT, if you read every character,
>> which one is really faster? I would expect TEXT to be a little faster,
>> since the server side will send the characters before they are asked
>> for. By faster, I mean from the application performance point of view. :)
>>
>> Could this be changed in a custom Oracle dialect? So new
>> applications/databases could perhaps use that and existing applications
>> might use LONGs a bit longer via the existing Oracle dialect.
>>
>> On 10/14/2011 09:22 PM, Gail Badner wrote:
>>> In [1], I am seeing the following type mappings:
>>>
>>> Column type: LONG -> java.sql.Types.LONGVARCHAR -> java.lang.String
>>> Column type: LONGRAW -> java.sql.Types.LONGVARBINARY -> byte[]
>>>
>>> org.hibernate.type.TextType is consistent with the mapping for LONG.
>>>
>>> org.hibernate.type.ImageType is consistent with the mapping for LONGRAW.
>>>
>>> From this standpoint, the current settings are appropriate.
>>>
>>> I understand there are restrictions when LONG and LONGRAW are used and I see from your other message that there is Oracle documentation for migrating to CLOB and BLOB.
>>>
>>> I agree that changing column type registration as follows (for Oracle only) should fix this:
>>> registerColumnType( Types.VARBINARY, 2000, "raw($l)" );
>>> registerColumnType( Types.VARBINARY, "blob" );
>>>
>>> registerColumnType( Types.LONGVARCHAR, "clob" );
>>> registerColumnType( Types.LONGVARBINARY, "blob" );
>>>
>>> registerColumnType( Types.VARCHAR, 4000, "varchar2($l char)" );
>>> registerColumnType( Types.VARCHAR, "clob" );
>>>
>>> Steve, what do you think? Is it too late to make this change for 4.0.0?
>>>
>>> [1] Table 11-1 of Oracle® Database JDBC Developer's Guide and Reference, 11g Release 1 (11.1) (http://download.oracle.com/docs/cd/B28359_01/java.111/b31224/datacc.htm#g...)
>>> [2] Hibernate Core Migration Guide for 3.5 (http://community.jboss.org/wiki/HibernateCoreMigrationGuide35)
>>> [3] Table 2-10 of Oracle® Database SQL Language Reference
>>> 11g Release 1 (11.1) (http://download.oracle.com/docs/cd/B28359_01/server.111/b28286/sql_elemen...)
>>>
>>> ----- Original Message -----
>>>> From: "Łukasz Antoniak"<lukasz.antoniak(a)gmail.com>
>>>> To: hibernate-dev(a)lists.jboss.org
>>>> Sent: Thursday, October 13, 2011 12:50:13 PM
>>>> Subject: [hibernate-dev] HHH-6726 LONG and LONG RAW column types in Oracle
>>>>
>>>> Welcome Community!
>>>>
>>>> I have just subscribed to the list and wanted to discuss HHH-6726
>>>> JIRA
>>>> issue.
>>>>
>>>> Gail Badner wrote
>>>> (http://lists.jboss.org/pipermail/hibernate-dev/2011-October/007208.html):
>>>> HHH-6726 (Oracle : map TextType to clob and ImageType to blob)
>>>> https://hibernate.onjira.com/browse/HHH-6726
>>>> There have been a number of issues opened since the change was made
>>>> to
>>>> map TextType (LONGVARCHAR) 'long' and ImageType (LONGVARBINARY) to
>>>> 'long
>>>> raw'. This change was already documented in the migration notes.
>>>> Should
>>>> the mapping for Oracle (only) be changed back to clob and blob?
>>>>
>>>> HHH-6726 is caused by an issue in Oracle JDBC driver (version
>>>> 10.2.0.4
>>>> and later). This bug appears when LONG or LONG RAW columns are
>>>> accessed
>>>> not as first or last while processing SQL statement.
>>>>
>>>> I have discussed the topic of mapping TextType to CLOB and ImageType
>>>> to
>>>> BLOB (only in Oracle dialect) with Strong Liu. Reasons for doing so:
>>>> - Oracle allows only one LONG / LONG RAW column per table. This might
>>>> be
>>>> the most important from Hibernate's perspective.
>>>> - LONG / LONG RAW - up to 2 GB, BLOB / CLOB - up to 4 GB.
>>>> - In PL/SQL using LOBs is more efficient (random access to data).
>>>> LONG
>>>> only sequential.
>>>> - LONG and LONG RAW are deprecated.
>>>>
>>>> What is your opinion?
>>>>
>>>> Regards,
>>>> Lukasz Antoniak
>>>> _______________________________________________
>>>> hibernate-dev mailing list
>>>> hibernate-dev(a)lists.jboss.org
>>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>>>>
>>> _______________________________________________
>>> hibernate-dev mailing list
>>> hibernate-dev(a)lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>> _______________________________________________
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>
8 years, 9 months
Changelog file in Hibernate ORM
by Sanne Grinovero
The file changelog.txt in the root ot the Hibernate ORM project seems outdated.
Is it not maintained anymore? I found it handy.
Sanne
9 years, 5 months
JdbcSession proposal
by Steve Ebersole
I found a few spare minutes to work on this a little and move it into
the next stage with some actual interfaces, impls and usages to help
illustrate some of the proposed concepts.
https://github.com/sebersole/JdbcSession
The README.md is very up-to-date and detailed. Would be good to get
input from others.
P.S. I probably dislike the *Inflow naming more than you do :)
10 years, 3 months
[Search] Index embedded and id property of embedded entity
by Hardy Ferentschik
Hi,
I started to look at HSEARCH-1494 [1] which deals with an unexpected exception is thrown when @IndexedEmbedded is used.
Easiest to explain with an example:
@Entity
@Indexed
public class A {
@Id
@GeneratedValue
private long id;
@OneToOne
@IndexedEmbedded
private B b;
}
@Entity
public class B {
@Id
@GeneratedValue
private Timestamp id;
@Field
private String foo;
public Timestamp getId() {
return id;
}
public String getFoo() {
return foo;
}
}
A includes B via @IndexedEmbedded and is only interested in including the ‘foo’ field. However, atm we implicitly index B.id as well.
In this particular case an exception is thrown, because we don’t know which field bridge to use for B.id.
This also relates to HSEARCH-1092 [2], where the include path feature of @IndexedEmbedded is used. Even though the configured
paths don’t include the ids, they are added which increases the index size unnecessarily (not really sure whether it really matters in practice).
If we skip the implicit inclusion of id properties, the user will need to add an explicit @Field in case he wants to include an id property via indexed
embedded. If the embedded entity itself is not indexed, I think this makes sense. But what if the embedded entity is indexed itself? Does it seem
wrong in this case to specify an additional @Field? Do we need some additional configuration element?
Thoughts?
—Hardy
[1] https://hibernate.atlassian.net/browse/HSEARCH-1494
[2] https://hibernate.atlassian.net/browse/HSEARCH-1092
10 years, 5 months
Making tests nicer with lambdas
by Gunnar Morling
Hey,
I've played around a bit with the idea of using Java 8 lambdas to make
tests easier to write and read. We have many tests which open a session and
TX, do some stuff, commit, open a new TX (and/or session), do some
assertions and so on:
Session session = openSession();
Transaction transaction = session.beginTransaction();
// heavy testing action...
transaction.commit();
session.clear();
transaction = session.beginTransaction();
// load, assert...
transaction.commit();
session.clear();
The same could look like this using Java 8 lambdas:
Foo foo = inTransactionWithResult( (session, tx) -> {
// heavy testing action...
} );
inTransaction( (session, tx) -> {
// load, assert...
} );
Extracting the session/TX handling removes quite some clutter and focuses
more on the actual testing logic. It also avoids problems due to dangling
transactions e.g. in case of assertion failures as the TX handling is done
in a finally block in inTransaction().
At this point I've just done a quick POC and would be interested in
feedback whether you think that's worth pursuing or not. Note that
different language levels can be used for test and main code, so we could
make use of lambdas in tests while ensuring Java 6 compatibility for the
delivered artifacts.
--Gunnar
10 years, 5 months
Envers: Mapped-superclasses extended by embeddabables
by Gail Badner
Hi Adam,
The relevant issues:
HHH-8908 : Envers: Column of Embedded missing in Audit Table
HHH-9194 : Revert HHH-8908 fix
HHH-9193 : Default audit behavior of a mapped-superclass is inconsistent when extended by an entity vs an embeddable
I created a pull request for reverting HHH-8908 (https://github.com/hibernate/hibernate-orm/pull/742). The fix is reverted for HHH-9194 and I've re-purposed the testcases that were added to HHH-8908 for HHH-9193. I'm still a little fuzzy of the expectations of these tests, so please take a look at the pull request and let me know if anything needs to be changed.
I'm still unsure how on the ways to explicitly enable auditing for a mapped-superclass as a whole or particular fields/methods. Here are some guesses on how I think it should work. Assume the following uses AccessType.FIELD.
In the following, A.b.intValue should be audited; A.b.strValue should not be audited.
@Entity
@Audited
public class A{
...
private B b;
...
}
@Embeddable
public class B extends AbstractB {
private int intValue;
}
@MappedSuperclass
public class AbstractB {
private String strValue;
}
In the following, both A.b.intValue and A.b.strValue should be audited:
@Entity
@Audited
@AuditOverride( name="b.strValue" )
public class A{
...
private B b;
...
}
@Embeddable
public class B extends AbstractB {
private int intValue;
}
@MappedSuperclass
public class AbstractB {
private String strValue;
}
In the following, both A.b.intValue and A.b.strValue should be audited:
@Entity
@Audited
public class A{
...
private B b;
...
}
@Embeddable
public class B extends AbstractB {
private int intValue;
}
@MappedSuperclass
@Audited
public class AbstractB {
private String strValue;
}
In the following, both A.b.intValue and A.b.strValue should be audited.
@Entity
@Audited
public class A{
...
private B b;
...
}
@Embeddable
@AuditOverride( class=AbstractB.class )
public class B extends AbstractB {
private int intValue;
}
@MappedSuperclass
public class AbstractB {
private String strValue;
}
What should be the outcome of the following? Should A.b.strValue still be audited even though A.b is explicitly not audited?
@Entity
@Audited
public class A{
...
@NotAudited
private B b;
...
}
@Embeddable
public class B extends AbstractB {
private int intValue;
}
@MappedSuperclass
@Audited
public class AbstractB {
private String strValue;
}
Please clarify or correct as necessary. At this point, I'm not sure which of the above cases work. Once the expected behavior is clarified, tests should be added to ensure that envers operates as expected. Jira issues should be added for cases that don't work.
Thanks,
Gail
10 years, 5 months
Changing method signatures in micro releases
by Gunnar Morling
Hi,
When updating Hibernate OGM to make use of ORM 4.3.5, I noticed a changed
method signature in AbstractCollectionPersister (abstract
method doProcessQueuedOps() has a new parameter).
This causes a compilation failure in OGM, as we naturally still override
the old signature. I can solve this particular case in a compatible manner
by declaring both variants of the method in our sub-class (omitting the
@Override annotation), but I'm wondering how we should generally deal with
this kind of issue.
Are micro-releases considered strictly backwards-compatible, so that e.g.
all of ORM 4.3.x should be useable together with an integrator (such as
OGM) known to work with 4.3.0? This would have been my assumption
originally.
Are there any rules for what kind of changes are to be expected by an ORM
micro/minor/major update?
Thanks,
--Gunnar
10 years, 6 months
