Not cleaned up commons pool's evictor task when SQLException occurs after the
GenericObjectPool is initialized in createDataSource.
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Key: DBCP-342
URL: https://issues.apache.org/jira/browse/DBCP-342
Project: Commons Dbcp
Issue Type: Bug
Affects Versions: 1.4
Environment: * commons-pool : 1.4
* commons-dbcp : 1.4, 1.3 both
* dbms : MSSQL 2007
Reporter: byungchol.kim
Fix For: 1.4.1
JIRA DBCP-93 bts is not fixed correctly
(JIRA DBCP-93 : If SQLException occurs after the GenericObjectPool is
initialized in createDataSource, the evictor task is not cleaned up)
Only one evictor timer thread leaves but evictor timer task queued as many as
createDataSource() method called.
queued evictor will keep tries to make connection to meet min idle connection.
if suddenly dbms become stable and can accept connection again,
then every queued evictor will try to make connection simultaneously.
In my case there were more then 100000 user requests while I set wrong password
to database,
when I change my password to correct in database
more then 100000 evictor tries to make connection
and finally mssql makes connections as many as integer limit and dbms dies.
here is my test.
{code:title=TestBasicDataSource.java}
public void testCreateDataSourceCleanupEvictor() throws Exception {
ds.close();
ds = null;
ds = createDataSource();
ds.setDriverClassName("org.apache.commons.dbcp.TesterConnRequestCountDriver");
ds.setUrl("jdbc:apache:commons:testerConnRequestCountDriver");
ds.setValidationQuery("SELECT DUMMY FROM DUAL");
ds.setUsername("username");
// Make password incorrect, so createDataSource will throw
ds.setPassword("wrong");
// Set timeBetweenEvictionRuns > 0, so evictor will be created
ds.setTimeBetweenEvictionRunsMillis(100);
// Set min idle > 0, so evictor will try to make connection as many as
idle count
ds.setMinIdle(2);
Class.forName("org.apache.commons.dbcp.TesterConnRequestCountDriver");
TesterConnRequestCountDriver testerDriver =
(TesterConnRequestCountDriver)
DriverManager.getDriver("jdbc:apache:commons:testerConnRequestCountDriver");
testerDriver.initConnRequestCount();
// user request 10 times
for (int i=0; i<10; i++) {
try {
@SuppressWarnings("unused")
DataSource ds2 = ds.createDataSource();
} catch (SQLException e) {
// Ignore
}
}
// sleep 1000ms. evictory will invoked 10 times.
Thread.sleep(1000);
// if orphan evictor is alive, connection request count will be 100
which is denoted from (ds.createDataSource() count * evictor invoke count)
// if DBMS connection is back to stable in 10 minutes then this test
case will make 120000 connections simultaneously
// 120000 connections = ds.createDataSource() count (10) *
evictor invoke count (6000) * min idle (2)
// but if evictor is cleaned up, connection request count will be only
10 (ds.createDataSource() count )
assertEquals(10, testerDriver.getConnectionRequestCount());
// fail to create datasource then clean up orphan connection pool and
evictor in connnection pool
assertNull(ds.connectionPool);
}
}
{code}
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