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
>> _______________________________________________
>> hibernate-dev mailing list
>> hibernate-dev(a)lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>
8 years, 11 months
Core: Has anyone broken the build?
by Emmanuel Bernard
Fresh from upstream
manu@dhcp-193-194 core (master) $ ./gradlew clean build
:buildSrc:compileJava UP-TO-DATE
:buildSrc:compileGroovy
Note: /Users/manu/projects/notbackedup/git/core/buildSrc/src/main/groovy/org/hibernate/gradle/testing/database/DatabaseMatrixPlugin.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
>>> a serious error occurred: hudson/util/DBAllocation
>>> stacktrace:
java.lang.NoClassDefFoundError: hudson/util/DBAllocation
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2427)
at java.lang.Class.getDeclaredMethods(Class.java:1791)
at org.codehaus.groovy.vmplugin.v5.Java5.configureClassNode(Java5.java:318)
at org.codehaus.groovy.ast.ClassNode.lazyClassInit(ClassNode.java:263)
at org.codehaus.groovy.ast.ClassNode.getInterfaces(ClassNode.java:341)
at org.codehaus.groovy.ast.ClassNode.declaresInterface(ClassNode.java:929)
at org.codehaus.groovy.ast.ClassNode.implementsInterface(ClassNode.java:909)
at org.codehaus.groovy.ast.ClassNode.isDerivedFromGroovyObject(ClassNode.java:899)
at org.codehaus.groovy.classgen.AsmClassGenerator.isGroovyObject(AsmClassGenerator.java:2752)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitPropertyExpression(AsmClassGenerator.java:2728)
at org.codehaus.groovy.ast.expr.PropertyExpression.visit(PropertyExpression.java:55)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitAndAutoboxBoolean(AsmClassGenerator.java:4122)
at org.codehaus.groovy.classgen.AsmClassGenerator.makeCallSite(AsmClassGenerator.java:2182)
at org.codehaus.groovy.classgen.AsmClassGenerator.makeCall(AsmClassGenerator.java:2019)
at org.codehaus.groovy.classgen.AsmClassGenerator.makeCall(AsmClassGenerator.java:2005)
at org.codehaus.groovy.classgen.AsmClassGenerator.makeInvokeMethodCall(AsmClassGenerator.java:1990)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitMethodCallExpression(AsmClassGenerator.java:2342)
at org.codehaus.groovy.ast.expr.MethodCallExpression.visit(MethodCallExpression.java:75)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitBooleanExpression(AsmClassGenerator.java:1959)
at org.codehaus.groovy.ast.expr.BooleanExpression.visit(BooleanExpression.java:40)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitIfElse(AsmClassGenerator.java:913)
at org.codehaus.groovy.ast.stmt.IfStatement.visit(IfStatement.java:41)
at org.codehaus.groovy.ast.CodeVisitorSupport.visitBlockStatement(CodeVisitorSupport.java:35)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitBlockStatement(ClassCodeVisitorSupport.java:165)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitBlockStatement(AsmClassGenerator.java:738)
at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:69)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitIfElse(AsmClassGenerator.java:921)
at org.codehaus.groovy.ast.stmt.IfStatement.visit(IfStatement.java:41)
at org.codehaus.groovy.ast.CodeVisitorSupport.visitBlockStatement(CodeVisitorSupport.java:35)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitBlockStatement(ClassCodeVisitorSupport.java:165)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitBlockStatement(AsmClassGenerator.java:738)
at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:69)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:101)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitConstructorOrMethod(ClassCodeVisitorSupport.java:112)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitStdMethod(AsmClassGenerator.java:626)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitConstructorOrMethod(AsmClassGenerator.java:601)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:123)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitMethod(AsmClassGenerator.java:696)
at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:1039)
at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:50)
at org.codehaus.groovy.classgen.AsmClassGenerator.visitClass(AsmClassGenerator.java:276)
at org.codehaus.groovy.control.CompilationUnit$12.call(CompilationUnit.java:748)
at org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:942)
at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:519)
at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:497)
at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:474)
at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:453)
at org.codehaus.groovy.tools.FileSystemCompiler.compile(FileSystemCompiler.java:67)
at org.codehaus.groovy.tools.FileSystemCompiler.doCompilation(FileSystemCompiler.java:180)
at org.codehaus.groovy.tools.FileSystemCompiler.commandLineCompile(FileSystemCompiler.java:148)
at org.codehaus.groovy.tools.FileSystemCompiler.main(FileSystemCompiler.java:162)
Caused by: java.lang.ClassNotFoundException: hudson.util.DBAllocation
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at groovy.lang.GroovyClassLoader.loadClass(GroovyClassLoader.java:696)
at groovy.lang.GroovyClassLoader.loadClass(GroovyClassLoader.java:793)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 52 more
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':compileGroovy'.
Cause: Forked groovyc returned error code: 1
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
BUILD FAILED
Total time: 6.849 secs
13 years, 2 months
docstyle questions
by Hardy Ferentschik
Hi,
I am having some question regarding the styles we are using.
I was looking for the source for org.hibernate:hibernate-jdocbook-style.
AFAICS, it is still in the svn repo:
https://svn.jboss.org/repos/hibernate/hibernate-jdocbook-style. Is this
correct?
And where do I find org.jboss:jbossorg-jdocbook-style? Who is responsible
for maintaining this style? PressGang?
Is there an issue tracker for this styles?
jbossorg-jdocbook-style contains documentation.css which determines the
look&feel of tables. Personally I find
the combination of no borders between table cells + a vertical middle
alignment of the content as not very suitable
for easy reading. Is that just me?
--hardy
13 years, 2 months
HHH-6735 Performance improvements in flush loop and more
by Emmanuel Bernard
Hi,
Sanne and I identified a few hot spots in Hibernate Core 4 especially when used with Hibernate OGM (which does use lighter weight datastores so to speak). The most significant one in term of code fix is HHH-6735 which now caches and guard FieldInterceptorHelper methods per class when a SessionFactory is known. This proves to be a significant performance boost for us. On simple CRUD operations (inserts I believe), we are about 50% faster. I believe this improvement will show up in regular Core users especially ones with big persistence context to flush.
Of course such a code change comes late in the 4.0 development cycle but I think it's worth it. Keep an eye on forums and JIRA for people complaining about bytecode enhanced classes not behaving as expected.
I've committed the change in master.
Emmanuel
13 years, 2 months
