Commons Dbcp
  1. Commons Dbcp
  2. DBCP-342

Not cleaned up commons pool's evictor task when SQLException occurs after the GenericObjectPool is initialized in createDataSource.

    Details

    • Type: Bug Bug
    • Status: Resolved
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: 1.3, 1.4
    • Fix Version/s: 1.3.1, 1.4.1
    • Labels:
      None
    • Environment:
      • commons-pool : 1.4
      • commons-dbcp : 1.4, 1.3 both
      • dbms : MSSQL 2007

      Description

      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.

      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);
          }
      }
      

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            • Assignee:
              Unassigned
              Reporter:
              byungchol.kim
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              • Created:
                Updated:
                Resolved:

                Development