1 JDBC Resource Registration on WebSphere Console javax.naming.InitialContext ctx = new javax.naming.InitialContext(); javax.sql.DataSource ds = (javax.sql.DataSource)ctx.lookup("jdbc/DB2UDB"); java.sql.Connection conn = ds.getConnection(); NO !!! Default: TRANSACTION_NONE Sharable Connection Information logging every called Servlet/JSP 코드에서 명시적으로 conn.close() 하였더라도 Servlet/JSP 가 끝날 때까지 connection 은 pool 로 release 되지 않음  불필요한 과도한 JDBC 연결자원사용됨 / 경우에 따라 성능장애

2 J2EE: DataSource Resource Reference when EAR packaging jdbc/DB2UDB User Application Database B WebSphere Application Server Transaction manager jdbc/MyDB Resource Manager EAR Resource Reference Mapping during deploy javax.naming.InitialContext ctx = new javax.naming.InitialContext(); javax.sql.DataSource ds = (javax.sql.DataSource)ctx.lookup(“java:comp/env/jdbc/MyDB"); java.sql.Connection conn = ds.getConnection(); register end request start to end with a thread lifetime Global JNDI name Local JNDI name

3 Using AAT, Datasource Resource Reference javax.naming.InitialContext ctx = new javax.naming.InitialContext(); javax.sql.DataSource ds = (javax.sql.DataSource)ctx.lookup("java:comp/env/jdbc/UnsharedDS"); java.sql.Connection conn = ds.getConnection(); 공유범위 : Shareable/Unshareable AAT  EAR 웹모듈  자원참조 유형 : DataSource

4 Using AAT, Transaction Isolation Level 동시성 제어 (Concurrency Control) 이슈 Transaction Isolation Level (1) TRANSACTION_NONE (default) (2) TRANSACTION_READ_UNCOMMITTED (3) TRANSACTION_READ_COMMITTED (4) TRANSACTION_REPEATABLE_READ (5) TRANSACTION_SERIALIZABLE 902 웹스피어 5.0 데이타베이스 연결 설정법

5 public void method() throws Exception { String name = getEmployeeName("7904"); String dept = getDeptName("1234"); } public String getEmployeeName(String id) throws Exception { Connection conn = null; Statement stmt = null; String name = null; try{ javax.sql.DataSource ds = (javax.sql.DataSource)ctx.lookup("java:comp/env/jdbc/A"); conn = ds.getConnection(); stmt = conn.createStatement(); Result rs = stmt.executeQuery("select ename from emp where empno = " + id); name = rs.getString("ename"); rs.close(); } finally{ if(stmt != null) try{stmt.close();}catch(Exception e){} if(conn != null) try{conn.close();}catch(Exception e){} } return name; } public String getDeptName(String id) throws Exception { Connection conn = null; Statement stmt = null; String name = null; try{ javax.sql.DataSource ds = (javax.sql.DataSource)ctx.lookup("java:comp/env/jdbc/A "); conn = ds.getConnection(); stmt = conn.createStatement(); Result rs = stmt.executeQuery("select deptname from dept where deptno = " + id); name = rs.getString("deptname"); rs.close(); } finally{ if(stmt != null) try{stmt.close();}catch(Exception e){} if(conn != null) try{conn.close();}catch(Exception e){} } return name; } Database B Resource Manager JDBC connection pool request end within a thread boundary Shareable Connection allocate release

6 public void method() throws Exception { String name = getEmployeeName("7904"); String dept = getDeptName("1234"); } public String getEmployeeName(String id) throws Exception { Connection conn = null; Statement stmt = null; String name = null; try{ javax.sql.DataSource ds = (javax.sql.DataSource)ctx.lookup("java:comp/env/jdbc/A"); conn = ds.getConnection(); stmt = conn.createStatement(); Result rs = stmt.executeQuery("select ename from emp where empno = " + id); name = rs.getString("ename"); rs.close(); } finally{ if(stmt != null) try{stmt.close();}catch(Exception e){} if(conn != null) try{conn.close();}catch(Exception e){} } return name; } public String getDeptName(String id) throws Exception { Connection conn = null; Statement stmt = null; String name = null; try{ javax.sql.DataSource ds = (javax.sql.DataSource)ctx.lookup("java:comp/env/jdbc/A "); conn = ds.getConnection(); stmt = conn.createStatement(); Result rs = stmt.executeQuery("select deptname from dept where deptno = " + id); name = rs.getString("deptname"); rs.close(); } finally{ if(stmt != null) try{stmt.close();}catch(Exception e){} if(conn != null) try{conn.close();}catch(Exception e){} } return name; } Database B Resource Manager JDBC connection pool Unshareable Connection allocate release allocate

7 XA and non-XA JDBC Driver Provider Non-XA JDBC Driver Provider javax.naming.InitialContext ctx = new javax.naming.InitialContext(); javax.sql.DataSource ds = (javax.sql.DataSource)ctx.lookup(“java:comp/env/jdbc/MyDB"); java.sql.Connection conn = ds.getConnection(); boolean mode = conn.getAutoCommit();  true XA JDBC Driver Provider javax.naming.InitialContext ctx = new javax.naming.InitialContext(); javax.sql.DataSource ds = (javax.sql.DataSource)ctx.lookup(" java:comp/env/jdbc/MyDB "); java.sql.Connection conn = ds.getConnection(); boolean mode = conn.getAutoCommit();  false Non-XA JDBC Driver Provider : 1-phase commit resource XA JDBC Driver Provider : 2-phase commit resource

8 Non-XA JDBC Resource EJB Servlet/JSP call() Database A WebSphere Application Server ctx.lookup("java:comp/env/jdbc/A"); Question : If - Unshareable Connection - Non-XA JDBC Provider Shareable needed Global Transaction error with 1pc resource !!

9 XA JDBC Provider : 2 phase-commit XA Resource manager XA Resource manager Transaction manager User Application tx.begin() tx.commit() Database A Database B 1 phase: prepare 2 phase: commit/rollback 1 phase: in-doubt 2 phase: commit/rollback tranlog WebSphere Application Server

10 XA JDBC Provider : 2 phase-commit XA Resource manager XA Resource manager EJB1 Database A Database B EJB2 Transaction propagation

11 java.sql.Connection conn1 = null; java.sql.Statement stmt1 = null; java.sql.Connection conn2 = null; java.sql.Statement stmt2 = null; javax.transaction.UserTransaction tx = null; try { javax.naming.InitialContext ctx = new javax.naming.InitialContext(); tx = (javax.transaction.UserTransaction) ctx.lookup("java:comp/UserTransaction"); tx.begin(); // javax.sql.DataSource ds1 = (javax.sql.DataSource)ctx.lookup("java:comp/env/jdbc/A"); conn1 = ds1.getConnection(); stmt1 = conn1.createStatement(); stmt1.executeUpdate("update emp set ename = 'LWY" + count + "' where empno = 7934"); // javax.sql.DataSource ds2 = (javax.sql.DataSource)ctx.lookup("java:comp/env/jdbc/B"); conn2 = ds2.getConnection(); stmt2 = conn2.createStatement(); stmt2.executeUpdate("update emp set ename = 'LWY" + count + "' where empno = 7934"); // tx.commit(); } catch(Exception e){ if ( tx != null ) try{tx.rollback();}catch(Exception ee){} } finally { if ( stmt1 != null ) try { stmt1.close();}catch(Exception e){} if ( conn1 != null ) try { conn1.close();}catch(Exception e){} if ( stmt2 != null ) try { stmt2.close();}catch(Exception e){} if ( conn2 != null ) try { conn2.close();}catch(Exception e){} } 2 phase commit sample (XA JDBC Datasource) Question : How about in EJB? CMT/BMT Database A Database B