[DERBY-4333] Exception in getMaxRows() after NullPointerException in SQLClob.readExternal() during query in table with CLOB column

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 10.5.1.1
• Fix Version/s: 10.5.2.0, 10.6.1.0
• Component/s: SQL
• Issue & fix info: High Value Fix, Repro attached
• Bug behavior facts: Regression
• Assignee: Kristian Waagan
• Reporter: Jason Ward
• Created: 03/Aug/09 18:45
• Updated: 04/Aug/09 12:16
• Resolved: 04/Aug/09 08:43

Description

Observed derby 10.5.1.1 throwing exception in getMaxRows() when querying table with greater than ~20K rows and CLOB column.

The exception is :

java.sql.SQLException: No current connection.
at org.apache.derby.client.am.SQLExceptionFactory.getSQLException(Unknown Source)
at org.apache.derby.client.am.SqlException.getSQLException(Unknown Source)
at org.apache.derby.client.am.Statement.getMaxRows(Unknown Source)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.getMaxRows(NewProxyPreparedStatement.java:1200)
at org.hibernate.jdbc.AbstractBatcher.closeQueryStatement(AbstractBatcher.java:298)
at org.hibernate.jdbc.AbstractBatcher.closeQueryStatement(AbstractBatcher.java:234)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1826)
at org.hibernate.loader.Loader.doQuery(Loader.java:697)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
at org.hibernate.loader.Loader.doList(Loader.java:2232)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129)
at org.hibernate.loader.Loader.list(Loader.java:2124)
at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:118)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1597)
at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:306)
at com.jw.TestMain.query(TestMain.java:175)
at com.jw.TestMain.main(TestMain.java:189)
Caused by: org.apache.derby.client.am.SqlException: No current connection.
at org.apache.derby.client.am.Statement.checkForClosedStatement(Unknown Source)

In digging into the stacktrace a little more it seems that hibernates call to getMaxRows() blows up because checkForClosedStatement() throws the SQLException, but I have no idea why. (I've verified the connection is open prior to executing hibenates list(), and it happens too quickly to be a true timeout.)

It only happens once my table reaches any significant size ( > 20K rows), and only on this particular table which includes a CLOB column.

Curiously 10.4.2.1 does not exhibit this behavior.

I have prepared a small eclipse project which repros the error and will attach.

Issue Links

• duplicates: DERBY-4245 Sorting a table containing a CLOB fails after upgrade to 10.5