[DERBY-4798] NPE in nested outer join

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 10.5.1.1, 10.5.2.0, 10.5.3.0, 10.6.1.0
• Fix Version/s: 10.5.3.2, 10.6.2.1, 10.7.1.1
• Component/s: SQL
• Bug behavior facts: Regression
• Assignee: Dag H. Wanvik
• Reporter: Dag H. Wanvik
• Created: 10/Sep/10 16:22
• Updated: 17/Jun/13 09:19
• Resolved: 17/Feb/11 17:33

Description

Using the schema from DERBY-4712 and running the original randomized query generator used to find DERBY-4712, http://code.google.com/p/h2database/source/browse/trunk/h2/src/test/org/h2/test/db/TestNestedJoins.java, I have uncovered yet another bug (NPE), which appears to be a different beast. This one is a regression in 10.5 (works in 10.4 and older). This is the failing query:

SELECT t0.x0,
t1.x1,
t2.x2,
t3.x3,
t4.x4,
t5.x5,
t6.x6,
t7.x7
FROM ((t0
LEFT OUTER JOIN ((t1
LEFT OUTER JOIN (t2
LEFT OUTER JOIN t3
ON t2.x2 = t3.x3 )
ON t1.x1 = t2.x2 )
LEFT OUTER JOIN (t4
INNER JOIN (t5
LEFT OUTER JOIN t6
ON t5.x5 = t6.x6 )
ON t4.x4 = t5.x5 )
ON t1.x1 = t5.x5 )
ON t0.x0 = t5.x5 )
LEFT OUTER JOIN t7
ON t3.x3 = t7.x7 );

Relevant part of the stack trace (using 10.5 trunk @ svn 995846):

Caused by: java.lang.NullPointerException
at org.apache.derby.impl.sql.execute.BaseActivation.getColumnFromRow(BaseActivation.java:1458)
at org.apache.derby.exe.ac4ac48095x012axfc73x9c5dx000003d485d847.e19(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.derby.impl.services.reflect.ReflectMethod.invoke(ReflectMethod.java:46)
at org.apache.derby.impl.sql.execute.GenericQualifier.getOrderable(GenericQualifier.java:96)
at org.apache.derby.impl.sql.execute.NoPutResultSetImpl.clearOrderableCache(NoPutResultSetImpl.java:307)
at org.apache.derby.impl.sql.execute.HashScanResultSet.resetProbeVariables(HashScanResultSet.java:359)
at org.apache.derby.impl.sql.execute.HashScanResultSet.openCore(HashScanResultSet.java:322)
at org.apache.derby.impl.sql.execute.JoinResultSet.openRight(JoinResultSet.java:283)
at org.apache.derby.impl.sql.execute.JoinResultSet.openCore(JoinResultSet.java:152)
at org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.openCore(ProjectRestrictResultSet.java:181)
at org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.open(BasicNoPutResultSetImpl.java:251)
at org.apache.derby.impl.sql.GenericPreparedStatement.executeStmt(GenericPreparedStatement.java:416)

Issue Links

• is related to: DERBY-3033 select query results in nullpointer exception in skipScan()
• is related to: DERBY-4712 Complex nested joins problems
• is related to: DERBY-3097 Unnecessary if statement can be removed from BaseActivation.getColumnFromNow
• is required by: DERBY-4994 10.5 backport effort issue (2011)