mysql & java & spring transaction isolation level

mysql

/*SESSION LEVEL*/
select @@tx_isolation;

/*GLOBAL LEVEL*/
select @@global.tx_isolation;

select 'SESSION' as scope,@@tx_isolation UNION
select 'GLOBAL' as scope,@@global.tx_isolation;
-- SESSION    REPEATABLE-READ
-- GLOBAL    REPEATABLE-READ

java.sql;

Connection

    /**
     * A constant indicating that transactions are not supported.
     */
    int TRANSACTION_NONE             = 0;

    /**
     * A constant indicating that
     * dirty reads, non-repeatable reads and phantom reads can occur.
     * This level allows a row changed by one transaction to be read
     * by another transaction before any changes in that row have been
     * committed (a "dirty read").  If any of the changes are rolled back,
     * the second transaction will have retrieved an invalid row.
     */
    int TRANSACTION_READ_UNCOMMITTED = 1;

    /**
     * A constant indicating that
     * dirty reads are prevented; non-repeatable reads and phantom
     * reads can occur.  This level only prohibits a transaction
     * from reading a row with uncommitted changes in it.
     */
    int TRANSACTION_READ_COMMITTED   = 2;

    /**
     * A constant indicating that
     * dirty reads and non-repeatable reads are prevented; phantom
     * reads can occur.  This level prohibits a transaction from
     * reading a row with uncommitted changes in it, and it also
     * prohibits the situation where one transaction reads a row,
     * a second transaction alters the row, and the first transaction
     * rereads the row, getting different values the second time
     * (a "non-repeatable read").
     */
    int TRANSACTION_REPEATABLE_READ  = 4;

    /**
     * A constant indicating that
     * dirty reads, non-repeatable reads and phantom reads are prevented.
     * This level includes the prohibitions in
     * <code>TRANSACTION_REPEATABLE_READ</code> and further prohibits the
     * situation where one transaction reads all rows that satisfy
     * a <code>WHERE</code> condition, a second transaction inserts a row that
     * satisfies that <code>WHERE</code> condition, and the first transaction
     * rereads for the same condition, retrieving the additional
     * "phantom" row in the second read.
     */
    int TRANSACTION_SERIALIZABLE     = 8;

    /**
     * Attempts to change the transaction isolation level for this
     * <code>Connection</code> object to the one given.
     * The constants defined in the interface <code>Connection</code>
     * are the possible transaction isolation levels.
     * <P>
     * <B>Note:</B> If this method is called during a transaction, the result
     * is implementation-defined.
     *
     * @param level one of the following <code>Connection</code> constants:
     *        <code>Connection.TRANSACTION_READ_UNCOMMITTED</code>,
     *        <code>Connection.TRANSACTION_READ_COMMITTED</code>,
     *        <code>Connection.TRANSACTION_REPEATABLE_READ</code>, or
     *        <code>Connection.TRANSACTION_SERIALIZABLE</code>.
     *        (Note that <code>Connection.TRANSACTION_NONE</code> cannot be used
     *        because it specifies that transactions are not supported.)
     * @exception SQLException if a database access error occurs, this
     * method is called on a closed connection
     *            or the given parameter is not one of the <code>Connection</code>
     *            constants
     * @see DatabaseMetaData#supportsTransactionIsolationLevel
     * @see #getTransactionIsolation
     */
    void setTransactionIsolation(int level) throws SQLException;

    /**
     * Retrieves this <code>Connection</code> object's current
     * transaction isolation level.
     *
     * @return the current transaction isolation level, which will be one
     *         of the following constants:
     *        <code>Connection.TRANSACTION_READ_UNCOMMITTED</code>,
     *        <code>Connection.TRANSACTION_READ_COMMITTED</code>,
     *        <code>Connection.TRANSACTION_REPEATABLE_READ</code>,
     *        <code>Connection.TRANSACTION_SERIALIZABLE</code>, or
     *        <code>Connection.TRANSACTION_NONE</code>.
     * @exception SQLException if a database access error occurs
     * or this method is called on a closed connection
     * @see #setTransactionIsolation
     */
    int getTransactionIsolation() throws SQLException;

org.springframework.transaction;

TransactionDefinitio/**

 * Interface that defines Spring-compliant transaction properties.
 * Based on the propagation behavior definitions analogous to EJB CMT attributes.
 *
 * <p>Note that isolation level and timeout settings will not get applied unless
 * an actual new transaction gets started. As only {@link #PROPAGATION_REQUIRED},
 * {@link #PROPAGATION_REQUIRES_NEW} and {@link #PROPAGATION_NESTED} can cause
 * that, it usually doesn't make sense to specify those settings in other cases.
 * Furthermore, be aware that not all transaction managers will support those
 * advanced features and thus might throw corresponding exceptions when given
 * non-default values.
 *
 * <p>The {@link #isReadOnly() read-only flag} applies to any transaction context,
 * whether backed by an actual resource transaction or operating non-transactionally
 * at the resource level. In the latter case, the flag will only apply to managed
 * resources within the application, such as a Hibernate {@code Session}.
 *
 * @author Juergen Hoeller
 * @since 08.05.2003
 * @see PlatformTransactionManager#getTransaction(TransactionDefinition)
 * @see org.springframework.transaction.support.DefaultTransactionDefinition
 * @see org.springframework.transaction.interceptor.TransactionAttribute
 */
public interface TransactionDefinition {

    /**
     * Support a current transaction; create a new one if none exists.
     * Analogous to the EJB transaction attribute of the same name.
     * <p>This is typically the default setting of a transaction definition,
     * and typically defines a transaction synchronization scope.
     */
    int PROPAGATION_REQUIRED = 0;

    /**
     * Support a current transaction; execute non-transactionally if none exists.
     * Analogous to the EJB transaction attribute of the same name.
     * <p><b>NOTE:</b> For transaction managers with transaction synchronization,
     * {@code PROPAGATION_SUPPORTS} is slightly different from no transaction
     * at all, as it defines a transaction scope that synchronization might apply to.
     * As a consequence, the same resources (a JDBC {@code Connection}, a
     * Hibernate {@code Session}, etc) will be shared for the entire specified
     * scope. Note that the exact behavior depends on the actual synchronization
     * configuration of the transaction manager!
     * <p>In general, use {@code PROPAGATION_SUPPORTS} with care! In particular, do
     * not rely on {@code PROPAGATION_REQUIRED} or {@code PROPAGATION_REQUIRES_NEW}
     * <i>within</i> a {@code PROPAGATION_SUPPORTS} scope (which may lead to
     * synchronization conflicts at runtime). If such nesting is unavoidable, make sure
     * to configure your transaction manager appropriately (typically switching to
     * "synchronization on actual transaction").
     * @see org.springframework.transaction.support.AbstractPlatformTransactionManager#setTransactionSynchronization
     * @see org.springframework.transaction.support.AbstractPlatformTransactionManager#SYNCHRONIZATION_ON_ACTUAL_TRANSACTION
     */
    int PROPAGATION_SUPPORTS = 1;

    /**
     * Support a current transaction; throw an exception if no current transaction
     * exists. Analogous to the EJB transaction attribute of the same name.
     * <p>Note that transaction synchronization within a {@code PROPAGATION_MANDATORY}
     * scope will always be driven by the surrounding transaction.
     */
    int PROPAGATION_MANDATORY = 2;

    /**
     * Create a new transaction, suspending the current transaction if one exists.
     * Analogous to the EJB transaction attribute of the same name.
     * <p><b>NOTE:</b> Actual transaction suspension will not work out-of-the-box
     * on all transaction managers. This in particular applies to
     * {@link org.springframework.transaction.jta.JtaTransactionManager},
     * which requires the {@code javax.transaction.TransactionManager} to be
     * made available it to it (which is server-specific in standard Java EE).
     * <p>A {@code PROPAGATION_REQUIRES_NEW} scope always defines its own
     * transaction synchronizations. Existing synchronizations will be suspended
     * and resumed appropriately.
     * @see org.springframework.transaction.jta.JtaTransactionManager#setTransactionManager
     */
    int PROPAGATION_REQUIRES_NEW = 3;

    /**
     * Do not support a current transaction; rather always execute non-transactionally.
     * Analogous to the EJB transaction attribute of the same name.
     * <p><b>NOTE:</b> Actual transaction suspension will not work out-of-the-box
     * on all transaction managers. This in particular applies to
     * {@link org.springframework.transaction.jta.JtaTransactionManager},
     * which requires the {@code javax.transaction.TransactionManager} to be
     * made available it to it (which is server-specific in standard Java EE).
     * <p>Note that transaction synchronization is <i>not</i> available within a
     * {@code PROPAGATION_NOT_SUPPORTED} scope. Existing synchronizations
     * will be suspended and resumed appropriately.
     * @see org.springframework.transaction.jta.JtaTransactionManager#setTransactionManager
     */
    int PROPAGATION_NOT_SUPPORTED = 4;

    /**
     * Do not support a current transaction; throw an exception if a current transaction
     * exists. Analogous to the EJB transaction attribute of the same name.
     * <p>Note that transaction synchronization is <i>not</i> available within a
     * {@code PROPAGATION_NEVER} scope.
     */
    int PROPAGATION_NEVER = 5;

    /**
     * Execute within a nested transaction if a current transaction exists,
     * behave like {@link #PROPAGATION_REQUIRED} else. There is no analogous
     * feature in EJB.
     * <p><b>NOTE:</b> Actual creation of a nested transaction will only work on
     * specific transaction managers. Out of the box, this only applies to the JDBC
     * {@link org.springframework.jdbc.datasource.DataSourceTransactionManager}
     * when working on a JDBC 3.0 driver. Some JTA providers might support
     * nested transactions as well.
     * @see org.springframework.jdbc.datasource.DataSourceTransactionManager
     */
    int PROPAGATION_NESTED = 6;
/**
     * Use the default timeout of the underlying transaction system,
     * or none if timeouts are not supported.
     */
    int TIMEOUT_DEFAULT = -1;

    /**
     * Return the propagation behavior.
     * <p>Must return one of the {@code PROPAGATION_XXX} constants
     * defined on {@link TransactionDefinition this interface}.
     * @return the propagation behavior
     * @see #PROPAGATION_REQUIRED
     * @see org.springframework.transaction.support.TransactionSynchronizationManager#isActualTransactionActive()
     */
    int getPropagationBehavior();

    /**
     * Return the isolation level.
     * <p>Must return one of the {@code ISOLATION_XXX} constants
     * defined on {@link TransactionDefinition this interface}.
     * <p>Only makes sense in combination with {@link #PROPAGATION_REQUIRED}
     * or {@link #PROPAGATION_REQUIRES_NEW}.
     * <p>Note that a transaction manager that does not support custom isolation levels
     * will throw an exception when given any other level than {@link #ISOLATION_DEFAULT}.
     * @return the isolation level
     */
    int getIsolationLevel();

    /**
     * Return the transaction timeout.
     * <p>Must return a number of seconds, or {@link #TIMEOUT_DEFAULT}.
     * <p>Only makes sense in combination with {@link #PROPAGATION_REQUIRED}
     * or {@link #PROPAGATION_REQUIRES_NEW}.
     * <p>Note that a transaction manager that does not support timeouts will throw
     * an exception when given any other timeout than {@link #TIMEOUT_DEFAULT}.
     * @return the transaction timeout
     */
    int getTimeout();

    /**
     * Return whether to optimize as a read-only transaction.
     * <p>The read-only flag applies to any transaction context, whether
     * backed by an actual resource transaction
     * ({@link #PROPAGATION_REQUIRED}/{@link #PROPAGATION_REQUIRES_NEW}) or
     * operating non-transactionally at the resource level
     * ({@link #PROPAGATION_SUPPORTS}). In the latter case, the flag will
     * only apply to managed resources within the application, such as a
     * Hibernate {@code Session}.
     <<     * <p>This just serves as a hint for the actual transaction subsystem;
     * it will <i>not necessarily</i> cause failure of write access attempts.
     * A transaction manager which cannot interpret the read-only hint will
     * <i>not</i> throw an exception when asked for a read-only transaction.
     * @return {@code true} if the transaction is to be optimized as read-only
     * @see org.springframework.transaction.support.TransactionSynchronization#beforeCommit(boolean)
     * @see org.springframework.transaction.support.TransactionSynchronizationManager#isCurrentTransactionReadOnly()
     */
    boolean isReadOnly();

    /**
     * Return the name of this transaction. Can be {@code null}.
     * <p>This will be used as the transaction name to be shown in a
     * transaction monitor, if applicable (for example, WebLogic's).
     * <p>In case of Spring's declarative transactions, the exposed name will be
     * the {@code fully-qualified class name + "." + method name} (by default).
     * @return the name of this transaction
     * @see org.springframework.transaction.interceptor.TransactionAspectSupport
     * @see org.springframework.transaction.support.TransactionSynchronizationManager#getCurrentTransactionName()
     */
    String getName();

}

org.springframework.transaction.annotation；

enum Isolation

/**
 * Enumeration that represents transaction isolation levels for use
 * with the {@link Transactional} annotation, corresponding to the
 * {@link TransactionDefinition} interface.
 *
 * @author Colin Sampaleanu
 * @author Juergen Hoeller
 * @since 1.2
 */
public enum Isolation {

    /**
     * Use the default isolation level of the underlying datastore.
     * All other levels correspond to the JDBC isolation levels.
     * @see java.sql.Connection
     */
    DEFAULT(TransactionDefinition.ISOLATION_DEFAULT),

    /**
     * A constant indicating that dirty reads, non-repeatable reads and phantom reads
     * can occur. This level allows a row changed by one transaction to be read by
     * another transaction before any changes in that row have been committed
     * (a "dirty read"). If any of the changes are rolled back, the second
     * transaction will have retrieved an invalid row.
     * @see java.sql.Connection#TRANSACTION_READ_UNCOMMITTED
     */
    READ_UNCOMMITTED(TransactionDefinition.ISOLATION_READ_UNCOMMITTED),

    /**
     * A constant indicating that dirty reads are prevented; non-repeatable reads
     * and phantom reads can occur. This level only prohibits a transaction
     * from reading a row with uncommitted changes in it.
     * @see java.sql.Connection#TRANSACTION_READ_COMMITTED
     */
    READ_COMMITTED(TransactionDefinition.ISOLATION_READ_COMMITTED),

    /**
     * A constant indicating that dirty reads and non-repeatable reads are
     * prevented; phantom reads can occur. This level prohibits a transaction
     * from reading a row with uncommitted changes in it, and it also prohibits
     * the situation where one transaction reads a row, a second transaction
     * alters the row, and the first transaction rereads the row, getting
     * different values the second time (a "non-repeatable read").
     * @see java.sql.Connection#TRANSACTION_REPEATABLE_READ
     */
    REPEATABLE_READ(TransactionDefinition.ISOLATION_REPEATABLE_READ),

    /**
     * A constant indicating that dirty reads, non-repeatable reads and phantom
     * reads are prevented. This level includes the prohibitions in
     * {@code ISOLATION_REPEATABLE_READ} and further prohibits the situation
     * where one transaction reads all rows that satisfy a {@code WHERE}
     * condition, a second transaction inserts a row that satisfies that
     * {@code WHERE} condition, and the first transaction rereads for the
     * same condition, retrieving the additional "phantom" row in the second read.
     * @see java.sql.Connection#TRANSACTION_SERIALIZABLE
     */
    SERIALIZABLE(TransactionDefinition.ISOLATION_SERIALIZABLE);

    private final int value;

    Isolation(int value) { this.value = value; }

    public int value() { return this.value; }

}

org.springframework.transaction;

TransactionDefinitio/**

    /**
     * Use the default isolation level of the underlying datastore.
     * All other levels correspond to the JDBC isolation levels.
     * @see java.sql.Connection
     */
    int ISOLATION_DEFAULT = -1;

    /**
     * Indicates that dirty reads, non-repeatable reads and phantom reads
     * can occur.
     * <p>This level allows a row changed by one transaction to be read by another
     * transaction before any changes in that row have been committed (a "dirty read").
     * If any of the changes are rolled back, the second transaction will have
     * retrieved an invalid row.
     * @see java.sql.Connection#TRANSACTION_READ_UNCOMMITTED
     */
    int ISOLATION_READ_UNCOMMITTED = Connection.TRANSACTION_READ_UNCOMMITTED;

    /**
     * Indicates that dirty reads are prevented; non-repeatable reads and
     * phantom reads can occur.
     * <p>This level only prohibits a transaction from reading a row
     * with uncommitted changes in it.
     * @see java.sql.Connection#TRANSACTION_READ_COMMITTED
     */
    int ISOLATION_READ_COMMITTED = Connection.TRANSACTION_READ_COMMITTED;

    /**
     * Indicates that dirty reads and non-repeatable reads are prevented;
     * phantom reads can occur.
     * <p>This level prohibits a transaction from reading a row with uncommitted changes
     * in it, and it also prohibits the situation where one transaction reads a row,
     * a second transaction alters the row, and the first transaction re-reads the row,
     * getting different values the second time (a "non-repeatable read").
     * @see java.sql.Connection#TRANSACTION_REPEATABLE_READ
     */
    int ISOLATION_REPEATABLE_READ = Connection.TRANSACTION_REPEATABLE_READ;

    /**
     * Indicates that dirty reads, non-repeatable reads and phantom reads
     * are prevented.
     * <p>This level includes the prohibitions in {@link #ISOLATION_REPEATABLE_READ}
     * and further prohibits the situation where one transaction reads all rows that
     * satisfy a {@code WHERE} condition, a second transaction inserts a row
     * that satisfies that {@code WHERE} condition, and the first transaction
     * re-reads for the same condition, retrieving the additional "phantom" row
     * in the second read.
     * @see java.sql.Connection#TRANSACTION_SERIALIZABLE
     */
    int ISOLATION_SERIALIZABLE = Connection.TRANSACTION_SERIALIZABLE;