Dénes Bodó created DBCP-595:
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Summary: Connection pool can be exhausted when connections are
killed on the DB side
Key: DBCP-595
URL: https://issues.apache.org/jira/browse/DBCP-595
Project: Commons DBCP
Issue Type: Bug
Affects Versions: 2.11.0
Reporter: Dénes Bodó
Apache Oozie 5.2.1 uses OpenJPA 2.4.2 and commons-dbcp 1.4 and commons-pool
1.5.4. These are ancient version, I know.
h1. Description
The issue is that when due to some network issues or "maintenance work" on the
DB side (especially PostgreSQL) which causes the DB connection to be closed, it
results exhausted Pool on the client side.
According to my observation this is because the JDBC driver does not get closed
on the client side, nor the abstract DBCP connection
_org.apache.commons.dbcp2.PoolableConnection_ .
h1. Repro
(Un)Fortunately I can reproduce the issue using the latest and greatest
commons-dbcp 2.11.0 and commons-pool 2.12.0 along with OpenJPA 3.2.2.
I've just created a Java application to reproduce the issue:
[https://github.com/dionusos/pool_exhausted_repro] . See README.md for detailed
repro steps.
h1. Kind of solution?
To be honest I am not really familiar with DBCP but with this change I managed
to make my application more robust:
{code:java}
diff --git a/src/main/java/org/apache/commons/dbcp2/PoolableConnection.java
b/src/main/java/org/apache/commons/dbcp2/PoolableConnection.java
index 440cb756..678550bf 100644
--- a/src/main/java/org/apache/commons/dbcp2/PoolableConnection.java
+++ b/src/main/java/org/apache/commons/dbcp2/PoolableConnection.java
@@ -214,6 +214,10 @@ public class PoolableConnection extends
DelegatingConnection<Connection> impleme
@Override
protected void handleException(final SQLException e) throws SQLException {
fatalSqlExceptionThrown |= isFatalException(e);
+ if (fatalSqlExceptionThrown && getDelegate() != null) {
+ getDelegate().close();
+ this.close();
+ }
super.handleException(e);
}{code}
What do you think about this approach?
Is it a completely dead-end or we can start working on it in this direction?
Do you agree that the reported and reproduced issue is a real one and nut just
some kind of misconfiguration?
I am lost at this point and I need to move forward so I am asking for guidance
here.
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