TX その19 ちょっとした進展

JBoss

エミュレーションコード

public void testTxManager() throws Exception {
    String url = "jdbc:mysql://localhost:3306/test";
    Class.forName("com.mysql.jdbc.Driver").newInstance();
    Connection conn = (com.mysql.jdbc.Connection)
        DriverManager.getConnection(url);
    XAResource xaResource = new MysqlXAConnection(conn);
    Connection conn2 = (com.mysql.jdbc.Connection)
        DriverManager.getConnection(url);
    XAResource xaResource2 = new MysqlXAConnection(conn2);
    
    TxManager tm = TxManager.getInstance();

    tm.begin();
    conn.setAutoCommit(false);
    conn2.setAutoCommit(false);
    Transaction tx = tm.getTransaction();
    tx.enlistResource(xaResource);
    tx.enlistResource(xaResource2);

    tm.commit();
    conn.close();
    conn2.close();
}

このコードを実行した際のMySQLのGeneral log

11 Connect     @localhost as anonymous on test
11 Query       SET NAMES latin1
11 Query       SET character_set_results = NULL
11 Query       SHOW VARIABLES
11 Query       SHOW COLLATION
11 Query       SET autocommit=1
12 Connect     @localhost as anonymous on test
12 Query       SET NAMES latin1
12 Query       SET character_set_results = NULL
12 Query       SHOW VARIABLES
12 Query       SHOW COLLATION
12 Query       SET autocommit=1
11 Query       SET autocommit=0
12 Query       SET autocommit=0
11 Query       XA START 0x6d697234322f31,0x31,0x101
12 Query       XA START 0x6d697234322f31,0x32,0x101
11 Query       XA END 0x6d697234322f31,0x31,0x101
12 Query       XA END 0x6d697234322f31,0x32,0x101
11 Query       XA PREPARE 0x6d697234322f31,0x31,0x101
12 Query       XA PREPARE 0x6d697234322f31,0x32,0x101
11 Query       XA COMMIT 0x6d697234322f31,0x31,0x101
12 Query       XA COMMIT 0x6d697234322f31,0x32,0x101
11 Query       rollback
11 Quit       
12 Query       rollback
12 Quit

conn2とかxaResource2とかをコメントアウトした場合，つまりXAResourceが1つである場合には，PREPAREを行わずにXA COMMIT...ONE PHASEとなる．

5 Connect     @localhost as anonymous on test
5 Query       SET NAMES latin1
5 Query       SET character_set_results = NULL
5 Query       SHOW VARIABLES
5 Query       SHOW COLLATION
5 Query       SET autocommit=1
5 Query       XA START 0x6d697234322f31,0x31,0x101
5 Query       XA END 0x6d697234322f31,0x31,0x101
5 Query       XA COMMIT 0x6d697234322f31,0x31,0x101 ONE PHASE
5 Quit

以前の謎が解けたね〜．