Hibernate在每次插入之前選擇標識列值

Question

我試圖在數據庫中插入30行，ID生成策略是IDENTITY而我的數據庫（Exasol）支持它。 在每次插入之前，Hibernate都會從數據庫中選擇標識值，如下所示（從Hibernate日志中）：

Hibernate:
    SELECT
            COLUMN_IDENTITY 
        FROM
            EXA_ALL_COLUMNS 
        WHERE
            COLUMN_NAME='ENTRY_ID' 
            AND COLUMN_SCHEMA='TEST' 
            AND COLUMN_TABLE='CAMPAIGN'
Hibernate: 
    insert 
    into
        ecombi_mdm_test.CSV_ADCAMPAIGN
        (bla1, bla2, bla3, bla4, bla5, bla6, bla7, bla8, bla9, bla10, bla11, bla12, bla13, bla14, bla15, bla16, bla17, bla18, bla19, bla20, bla21, bla22, bla23, bla24, bla25, bla26, bla27, bla28, bla29, bla30) 
    values
        (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate:
    SELECT
            COLUMN_IDENTITY 
        FROM
            EXA_ALL_COLUMNS 
        WHERE
            COLUMN_NAME='ENTRY_ID' 
            AND COLUMN_SCHEMA='TEST' 
            AND COLUMN_TABLE='CAMPAIGN'
Hibernate: 
    insert 
    into
        ecombi_mdm_test.CSV_ADCAMPAIGN
        (bla1, bla2, bla3, bla4, bla5, bla6, bla7, bla8, bla9, bla10, bla11, bla12, bla13, bla14, bla15, bla16, bla17, bla18, bla19, bla20, bla21, bla22, bla23, bla24, bla25, bla26, bla27, bla28, bla29, bla30) 
    values
        (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)

...還有28個。 最后，我花了9秒鍾才能插入30行。

這是我配置數據源的方式：

        configuration = new Configuration();
        configuration.setProperty("hibernate.connection.driver_class", properties.getProperty(...);
        configuration.setProperty("hibernate.connection.url", properties.getProperty(...);
        configuration.setProperty("hibernate.connection.username", properties.getProperty(...);
        configuration.setProperty("hibernate.connection.password", properties.getProperty(...);
        configuration.setProperty("hibernate.dialect", properties.getProperty(com.bla.exasol.ExasolDialect);
        configuration.setProperty("hibernate.show_sql", "true");
        configuration.setProperty("hibernate.format_sql", "true");
        configuration.setProperty("hibernate.default_schema", properties.getProperty(...);
        configuration.addAnnotatedClass(Some.class);

        ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
        SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry);

這是從我的DAO課上獲得的：

Session session = MultiTenantDBAccess.getSessionFactory().openSession();
Transaction transaction = null;

try {
    transaction = session.beginTransaction();
    for (T o : oList) {
        session.persist(o);
    }
    transaction.commit();
} catch (HibernateException e) {
    transaction.rollback();
    e.printStackTrace();
} finally {
    session.close();
}

這是我的數據庫的自定義身份支持類：

public class ExasolIdentityColumnSupport extends IdentityColumnSupportImpl {

    @Override
    public String appendIdentitySelectToInsert(String arg0) {
        return arg0;
    }

    @Override
    public String getIdentityColumnString(int type) throws MappingException {
        return type==Types.BIGINT ?
                "decimal(36, 0) identity not null" :
                "decimal(19, 0) identity not null";
    }

    @Override
    public String getIdentitySelectString(String table, String column, int type) throws MappingException {
        return "SELECT COLUMN_IDENTITY FROM EXA_ALL_COLUMNS WHERE COLUMN_NAME='"+column.toUpperCase()+"' AND COLUMN_SCHEMA='"+table.substring(0, table.indexOf(".")).toUpperCase()+"' AND COLUMN_TABLE='"+(table.substring(table.indexOf(".")+1)).toUpperCase()+"'";
    }

    @Override
    public boolean hasDataTypeInIdentityColumn() {
        return false;
    }

    @Override
    public boolean supportsIdentityColumns() {
        return true;
    }

    public boolean supportsInsertSelectIdentity() {
        return false;
    }

}

問題是我使用的數據庫不支持InsertSelectIdentity嗎？ Hibernate是否不能在每次插入之前不檢查id值就向數據庫發送30個查詢？ 在這種情況下，我無法通過Hibernate獲得比每9秒30行更好的性能嗎？

Answer 1

需要使用ID，因為實體是使用ID作為鍵存儲在會話中的。

如果數據庫支持使用序列，則規避它的唯一方法是使用數據庫序列。

Answer 2

對OLTP工作負載使用列式分析DMBS不是一個好主意：選擇，插入或更新單行。

您可以使用MySQL / PostgreSQL等來存儲作業狀態和普遍的ORM悲傷。 並將Exasol僅用於大數據批次和大導入。