테스트 목적
Java 의 Connection 과 Oracle 의 session 간의 관계 확인
가정
IBATIS 설정 MaximumActiveConnections 까지 점차적으로 Connection 수를 증가시키면
매 증가시 마다 오라클 session 수가 늘어날 것이다.
실험
1. 연결 유지를 위한 무한루프 프로시저
2. SQLMap
3. 5초마다 하나씩 커넥션을 늘리고, 연결정보를 출력하는 자바 어플리케이션
4. 결과
테스트 어플리케이션이 실행되면 매 5초 마다 새로운 커넥션이 생성되므로
오라클에서 다음 쿼리를 이용해 session 수의 증가를 확인
take 0
activeConnections 는 MaximumActiveConnections의 제한 수치인 50에서 더이상 증가하지 않고
take 51 에서 멈춘다. 내부적으로 take51 는 다음과 같은 Stack trace 를 나타내고 있다.
오라클의 세션수는 take n 의 n 수와 일치하며 take 51 시점의 세션수는 이미 한계치에 도달했으므로 더 이상 증가하지 않는다.
Java 의 Connection 과 Oracle 의 session 간의 관계 확인
가정
IBATIS 설정 MaximumActiveConnections 까지 점차적으로 Connection 수를 증가시키면
매 증가시 마다 오라클 session 수가 늘어날 것이다.
실험
1. 연결 유지를 위한 무한루프 프로시저
CREATE OR REPLACE PROCEDURE SP_LOOP
is
begin
loop
null;
end loop;
end;
2. SQLMap
<sqlMap>
<procedure id="loop">
{call sp_loop}
</procedure>
</sqlMap>
3. 5초마다 하나씩 커넥션을 늘리고, 연결정보를 출력하는 자바 어플리케이션
import java.sql.SQLException;
import com.ibatis.common.jdbc.SimpleDataSource;
import com.ibatis.sqlmap.client.SqlMapClient;
public class ConnectionTest
{
public static void main(String[] args) throws InterruptedException
{
init();
int i = 0;
while (true)
{
Thread t = new Thread(new Runnable()
{
@Override
public void run()
{
try
{
sqlMapClient.queryForList("loop");
}
catch (SQLException e)
{
e.printStackTrace();
}
}
});
System.out.println("take " + i++);
t.start();
System.out.println(((SimpleDataSource) sqlMapClient.getDataSource()).getStatus());
Thread.sleep(5000);
}
}
private static SqlMapClient sqlMapClient = null;
private static void init()
{
// IBATIS 초기화(생략)
}
}
4. 결과
테스트 어플리케이션이 실행되면 매 5초 마다 새로운 커넥션이 생성되므로
오라클에서 다음 쿼리를 이용해 session 수의 증가를 확인
SELECT status, count(*)
FROM v$session where username='test' AND program='JDBC Thin Client'
GROUP BY status
그리고 자바 어플리케이션을 실행하면 다음과 같은 로그가 나타난다.
take 0
===============================================================
jdbcDriver oracle.jdbc.OracleDriver
jdbcUrl jdbc:oracle:thin:test/************@127.0.0.1:1521:xe
jdbcUsername test
jdbcPassword ************
poolMaxActiveConnections 50
poolMaxIdleConnections 10
poolMaxCheckoutTime 120000
poolTimeToWait 300
poolPingEnabled false
poolPingQuery select 1 from dual
poolPingConnectionsOlderThan 1
poolPingConnectionsNotUsedFor 1
--------------------------------------------------------------
activeConnections 0
idleConnections 0
requestCount 0
averageRequestTime 0
averageCheckoutTime 0
claimedOverdue 0
averageOverdueCheckoutTime 0
hadToWait 0
averageWaitTime 0
badConnectionCount 0
===============================================================
DEBUG [00:08:40.544] {Thread-1} (Log4jImpl.java:26) Created connection 2040402337.
DEBUG [00:08:40.550] {Thread-1} (Log4jImpl.java:26) {conn-100000} Connection
DEBUG [00:08:40.554] {Thread-1} (Log4jImpl.java:26) {conn-100000} Preparing Call: {call sp_loop}
DEBUG [00:08:40.679] {Thread-1} (Log4jImpl.java:26) {pstm-100001} Executing Statement: {call sp_loop}
DEBUG [00:08:40.680] {Thread-1} (Log4jImpl.java:26) {pstm-100001} Parameters: []
DEBUG [00:08:40.680] {Thread-1} (Log4jImpl.java:26) {pstm-100001} Types: []
take 1
===============================================================
jdbcDriver oracle.jdbc.OracleDriver
jdbcUrl jdbc:oracle:thin:test/************@127.0.0.1:1521:xe
jdbcUsername test
jdbcPassword ************
poolMaxActiveConnections 50
poolMaxIdleConnections 10
poolMaxCheckoutTime 120000
poolTimeToWait 300
poolPingEnabled false
poolPingQuery select 1 from dual
poolPingConnectionsOlderThan 1
poolPingConnectionsNotUsedFor 1
--------------------------------------------------------------
activeConnections 1
idleConnections 0
requestCount 2
averageRequestTime 919
averageCheckoutTime 0
claimedOverdue 0
averageOverdueCheckoutTime 0
hadToWait 0
averageWaitTime 0
badConnectionCount 0
===============================================================
DEBUG [00:08:45.637] {Thread-2} (Log4jImpl.java:26) Created connection 435456241.
DEBUG [00:08:45.637] {Thread-2} (Log4jImpl.java:26) {conn-100002} Connection
DEBUG [00:08:45.638] {Thread-2} (Log4jImpl.java:26) {conn-100002} Preparing Call: {call sp_loop}
DEBUG [00:08:45.638] {Thread-2} (Log4jImpl.java:26) {pstm-100003} Executing Statement: {call sp_loop}
DEBUG [00:08:45.639] {Thread-2} (Log4jImpl.java:26) {pstm-100003} Parameters: []
DEBUG [00:08:45.639] {Thread-2} (Log4jImpl.java:26) {pstm-100003} Types: []
take 2
===============================================================
jdbcDriver oracle.jdbc.OracleDriver
jdbcUrl jdbc:oracle:thin:test/************@127.0.0.1:1521:xe
jdbcUsername test
jdbcPassword ************
poolMaxActiveConnections 50
poolMaxIdleConnections 10
poolMaxCheckoutTime 120000
poolTimeToWait 300
poolPingEnabled false
poolPingQuery select 1 from dual
poolPingConnectionsOlderThan 1
poolPingConnectionsNotUsedFor 1
--------------------------------------------------------------
activeConnections 2
idleConnections 0
requestCount 2
averageRequestTime 919
averageCheckoutTime 0
claimedOverdue 0
averageOverdueCheckoutTime 0
hadToWait 0
averageWaitTime 0
badConnectionCount 0
===============================================================
DEBUG [00:08:50.861] {Thread-3} (Log4jImpl.java:26) Created connection 39288954.
DEBUG [00:08:50.861] {Thread-3} (Log4jImpl.java:26) {conn-100004} Connection
DEBUG [00:08:50.862] {Thread-3} (Log4jImpl.java:26) {conn-100004} Preparing Call: {call sp_loop}
DEBUG [00:08:50.862] {Thread-3} (Log4jImpl.java:26) {pstm-100005} Executing Statement: {call sp_loop}
DEBUG [00:08:50.862] {Thread-3} (Log4jImpl.java:26) {pstm-100005} Parameters: []
DEBUG [00:08:50.863] {Thread-3} (Log4jImpl.java:26) {pstm-100005} Types: []
take 3
===============================================================
jdbcDriver oracle.jdbc.OracleDriver
jdbcUrl jdbc:oracle:thin:test/************@127.0.0.1:1521:xe
jdbcUsername test
jdbcPassword ************
poolMaxActiveConnections 50
poolMaxIdleConnections 10
poolMaxCheckoutTime 120000
poolTimeToWait 300
poolPingEnabled false
poolPingQuery select 1 from dual
poolPingConnectionsOlderThan 1
poolPingConnectionsNotUsedFor 1
--------------------------------------------------------------
activeConnections 3
idleConnections 0
requestCount 3
averageRequestTime 686
averageCheckoutTime 0
claimedOverdue 0
averageOverdueCheckoutTime 0
hadToWait 0
averageWaitTime 0
badConnectionCount 0
===============================================================
DEBUG [00:08:57.057] {Thread-4} (Log4jImpl.java:26) Created connection 2008400431.
DEBUG [00:08:57.058] {Thread-4} (Log4jImpl.java:26) {conn-100006} Connection
DEBUG [00:08:57.058] {Thread-4} (Log4jImpl.java:26) {conn-100006} Preparing Call: {call sp_loop}
DEBUG [00:08:57.058] {Thread-4} (Log4jImpl.java:26) {pstm-100007} Executing Statement: {call sp_loop}
DEBUG [00:08:57.059] {Thread-4} (Log4jImpl.java:26) {pstm-100007} Parameters: []
DEBUG [00:08:57.059] {Thread-4} (Log4jImpl.java:26) {pstm-100007} Types: []
.
.
.
(중략)
.
.
.
take 49
===============================================================
jdbcDriver oracle.jdbc.OracleDriver
jdbcUrl jdbc:oracle:thin:test/************@127.0.0.1:1521:xe
jdbcUsername test
jdbcPassword ************
poolMaxActiveConnections 50
poolMaxIdleConnections 10
poolMaxCheckoutTime 120000
poolTimeToWait 300
poolPingEnabled false
poolPingQuery select 1 from dual
poolPingConnectionsOlderThan 1
poolPingConnectionsNotUsedFor 1
--------------------------------------------------------------
activeConnections 49
idleConnections 0
requestCount 49
averageRequestTime 1653
averageCheckoutTime 0
claimedOverdue 0
averageOverdueCheckoutTime 0
hadToWait 0
averageWaitTime 0
badConnectionCount 0
===============================================================
DEBUG [00:12:59.662] {Thread-50} (Log4jImpl.java:26) Created connection 630515574.
DEBUG [00:12:59.662] {Thread-50} (Log4jImpl.java:26) {conn-100098} Connection
DEBUG [00:12:59.663] {Thread-50} (Log4jImpl.java:26) {conn-100098} Preparing Call: {call sp_loop}
DEBUG [00:12:59.663] {Thread-50} (Log4jImpl.java:26) {pstm-100099} Executing Statement: {call sp_loop}
DEBUG [00:12:59.664] {Thread-50} (Log4jImpl.java:26) {pstm-100099} Parameters: []
DEBUG [00:12:59.664] {Thread-50} (Log4jImpl.java:26) {pstm-100099} Types: []
take 50
===============================================================
jdbcDriver oracle.jdbc.OracleDriver
jdbcUrl jdbc:oracle:thin:test/************@127.0.0.1:1521:xe
jdbcUsername test
jdbcPassword ************
poolMaxActiveConnections 50
poolMaxIdleConnections 10
poolMaxCheckoutTime 120000
poolTimeToWait 300
poolPingEnabled false
poolPingQuery select 1 from dual
poolPingConnectionsOlderThan 1
poolPingConnectionsNotUsedFor 1
--------------------------------------------------------------
activeConnections 50
idleConnections 0
requestCount 50
averageRequestTime 1687
averageCheckoutTime 0
claimedOverdue 0
averageOverdueCheckoutTime 0
hadToWait 0
averageWaitTime 0
badConnectionCount 0
===============================================================
take 51
take 51 에서 멈춘다. 내부적으로 take51 는 다음과 같은 Stack trace 를 나타내고 있다.
Name: Thread-51
State: BLOCKED on oracle.jdbc.driver.T4CConnection@6c63a721 owned by: Thread-1
Total blocked: 1 Total waited: 0
Stack trace:
oracle.jdbc.driver.PhysicalConnection.rollback(PhysicalConnection.java:3689)
com.ibatis.common.jdbc.SimpleDataSource.popConnection(SimpleDataSource.java:600)
- locked java.lang.Object@7d7082d8
com.ibatis.common.jdbc.SimpleDataSource.getConnection(SimpleDataSource.java:222)
...
...
STATUS COUNT(*)
-------- ----------
-------- ----------
ACTIVE 50
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