Generation clauses which mention user-coded functions may produce different resuls depending on who performs the triggering INSERT/UPDATE

• Key: DERBY-3945
• Type: Bug
• Status: Resolved
• Resolution: Fixed
• Priority: Major
• Assignee: Rick Hillegas
• Reporter: Rick Hillegas
• Component/s: SQL
• Affects Version/s: 10.5.1.1
• Fix Version/s: 10.5.1.1

Description

This is similar to DERBY-3944. The compiler uses the current schema in order to resolve unqualifed function names when preparing INSERT/UPDATE statement. This means that a generation clause may evaluate differently depending on who invokes the triggering INSERT/UPDATE statement. This violates the requirement that generation clause should be deterministic (see part 2 of the ANSI/ISO standard, section 4.16.

Hopefully, the same patch will fix both DERBY-3944 and this issue.

Comments

[Rick Hillegas]

Attaching zz.sql, a script which demonstrates the problem.

[Rick Hillegas]

Attaching derby-3945-01-aa-functionSchema.diff. This patch forces Derby to use the current schema at DDL time (rather than DML time) to resolve unqualified function references in generation clauses. Running tests now.

There are two pieces to this fix:

1) The persisted default descriptor now stores the current schema which was in effect when the generation clause was defined.

2) At INSERT/UPDATE time, that saved schema temporarily becomes the current schema when we bind the generation clause.

A similar approach could be used for the related bugs having to do with unqualified function names in CHECK constraints (DERBY-3944) and VIEWS (DERBY-3953). Note that this approach does not address the related issues with dblook (DERBY-3954).


Touches the following files:

M java/engine/org/apache/derby/catalog/DefaultInfo.java
M java/engine/org/apache/derby/catalog/types/DefaultInfoImpl.java

Adds the DDL-time current schema to the default descriptor.


M java/engine/org/apache/derby/impl/sql/compile/TableElementList.java

Stuffs the current schema into the default descriptor at CREATE/ALTER time.


M java/engine/org/apache/derby/impl/sql/compile/DMLModStatementNode.java

Temporarily sets the current schema to the schema stored in the default when we bind generation clauses.


M java/testing/org/apache/derbyTesting/functionTests/tests/lang/GeneratedColumnsPermsTest.java

Adds tests.

[Rick Hillegas]

Regression tests ran cleanly for me except for two errors which look like they were introduced by someone else's checkin today. Committed at subversion revision revision 719123. The two errors were:

There were 2 errors:
1) testDefaultValues(org.apache.derbyTesting.unitTests.junit.CharacterStreamDescriptorTest)java.lang.NoClassDefFoundError: org/apache/derby/iapi/jdbc/CharacterStreamDescriptor$Builder
at org.apache.derbyTesting.unitTests.junit.CharacterStreamDescriptorTest.testDefaultValues(CharacterStreamDescriptorTest.java:42)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at org.apache.derbyTesting.junit.BaseTestCase.runBare(BaseTestCase.java:105)
2) testSetValues(org.apache.derbyTesting.unitTests.junit.CharacterStreamDescriptorTest)java.lang.NoClassDefFoundError: org/apache/derby/iapi/jdbc/CharacterStreamDescriptor$Builder
at org.apache.derbyTesting.unitTests.junit.CharacterStreamDescriptorTest.testSetValues(CharacterStreamDescriptorTest.java:67)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at org.apache.derbyTesting.junit.BaseTestCase.runBare(BaseTestCase.java:105)

FAILURES!!!
Tests run: 8900, Failures: 0, Errors: 2

[Dag H. Wanvik]

Similar problem and possibly solution as DERBY-3270, linking.

[Dag H. Wanvik]

Patch looks good!
Note: The constructor of DefaultInfoImpl now lacks some @params in its javadoc.

[Rick Hillegas]

Thanks for the review, Dag. Attaching derby-3945-02-aa-javadoc.diff, which address the javadoc issue. Committed at subversion revision 722177.