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From "Phil Steitz (JIRA)" <j...@apache.org>
Subject [jira] [Resolved] (DBCP-342) Not cleaned up commons pool's evictor task when SQLException occurs after the GenericObjectPool is initialized in createDataSource.
Date Mon, 25 Apr 2011 18:39:03 GMT

     [ https://issues.apache.org/jira/browse/DBCP-342?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Phil Steitz resolved DBCP-342.
------------------------------

    Resolution: Fixed

Modified version of the patch applied in r1096550 (trunk) and r1096550 (1.4.x branch).  I
made the following changes to the patch:
1. Instead of letting the Evictor start and shutting it down on exception, I moved the timeBetweenEvictionRuns
setter into a new startPoolMaintenance method that is not invoked until initialization has
succeeded.  This prevents connection requests getting fired while initialization is in progress.
2. Separated exception management for factory and instance creation.
3. Made closeConnectionPool swallow rather than propagate exceptions so that the main exception
leading to its invocation is not lost.
4. Changed the test class to not depend on DriverManager driver loading, which no longer happens
by default.

Thanks for the patch!


> Not cleaned up commons pool's evictor task when SQLException occurs after the GenericObjectPool
is initialized in createDataSource.
> -----------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: DBCP-342
>                 URL: https://issues.apache.org/jira/browse/DBCP-342
>             Project: Commons Dbcp
>          Issue Type: Bug
>    Affects Versions: 1.3, 1.4
>         Environment: * commons-pool : 1.4
> * commons-dbcp : 1.4, 1.3 both
> * dbms : MSSQL 2007
>            Reporter: byungchol.kim
>             Fix For: 1.3.1, 1.4.1
>
>         Attachments: dbcp_orphan_evictor_fix_patch.txt
>
>
> 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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