Hibernate的慢收购Postgres的连接Hibernate的慢收购Postgres的连接(H

我有一个非常困难的时候，调试这个问题。每当我尝试建立与Postgres的连接，需要整整分钟。在连接建立后，一切都很好。我试图禁用所有的映射，不加载任何，但仍连接需要较长的时间将收购。我也尝试禁用验证，没有什么区别。当我用一个简单的一个简单的JDBC连接，这是瞬间的。 Hibernate是为了做一些这需要相当长的时间，我似乎无法将它缩小。任何输入，非常感谢！

Postgres的驱动程序：

postgresql-9.1-901.jdbc4.jar

配置设置：

<hibernate-configuration>
    <session-factory>
    <!-- properties -->
        <property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>
        <property name="connection.driver_class">org.postgresql.Driver</property>

        <property name="connection.url">jdbc:postgresql://xxxx.com:5432/xxxxx</property>
        <property name="connection.username">xxxxxxx</property>
        <property name="connection.password">xxxxxxx</property>

    </session-factory>
</hibernate-configuration>

在代码中的其他设置：

    config.setProperty("hibernate.hbm2ddl.auto", hbm2ddlMode);
    //config.setProperty("hibernate.cache.use_query_cache", "true");
    config.setProperty("hibernate.cache.use_second_level_cache", "true");
    //config.setProperty("hibernate.cache.region.factory_class", "net.sf.ehcache.hibernate.EhCacheRegionFactory");
    config.setProperty("hibernate.cache.provider_class", "org.hibernate.cache.EhCacheProvider");
    //config.setProperty("hibernate.cache.provider_class", "org.hibernate.cache.NoCacheProvider");
    config.setProperty("hibernate.jdbc.fetch_size", "100");
    config.setProperty("hibernate.jdbc.batch_size", "30");
    config.setProperty("hibernate.jdbc.use_scrollable_resultset", "true");
    config.setProperty("hibernate.connection.provider_class", "org.hibernate.connection.C3P0ConnectionProvider");

    config.setProperty("hibernate.c3p0.acquire_increment", "1");
    config.setProperty("hibernate.c3p0.idle_test_period", "0");
    config.setProperty("hibernate.c3p0.min_size", "1");
    config.setProperty("hibernate.c3p0.max_size", "2");
    config.setProperty("hibernate.c3p0.timeout", "0");
    config.setProperty("javax.persistence.validation.mode", "none");

这里的代码段在延迟发生：

private SessionFactory buildSessionFactory() throws Exception {
        ServiceRegistry serviceRegistry  = new ServiceRegistryBuilder().applySettings(config.getProperties()).buildServiceRegistry();

            //Building session takes a whole minute without mappings!!!
        sessionFactory = config.buildSessionFactory(serviceRegistry);

        validateConnection();

        return sessionFactory;
    }

这里的日志结果：

[main] 2012-04-09 10:40:32,823 110391 INFO  C3P0ConnectionProvider - HHH000046: 
Connection properties: {user=hgaidb_test, password=****}
[main] 2012-04-09 10:40:32,823 110391 INFO  C3P0ConnectionProvider - HHH000006: 
Autocommit mode: false
[main] 2012-04-09 10:40:34,100 111668 DEBUG JdbcServicesImpl - Database ->
       name : PostgreSQL
    version : 8.3.3
      major : 8
      minor : 3
[main] 2012-04-09 10:40:34,101 111669 DEBUG JdbcServicesImpl - Driver ->
       name : PostgreSQL Native Driver
    version : PostgreSQL 9.1 JDBC4 (build 901)
      major : 9
      minor : 1
*******************************************************************************
// 1 MINUTE DELAY
*******************************************************************************
[main] 2012-04-09 10:40:34,102 111670 DEBUG JdbcServicesImpl - JDBC version : 4.
0
[main] 2012-04-09 10:41:21,632 159200 INFO  Dialect - HHH000400: Using dialect: 
org.hibernate.dialect.PostgreSQLDialect
*******************************************************************************
[main] 2012-04-09 10:41:21,669 159237 INFO  LobCreatorBuilder - HHH000424: Disab
ling contextual LOB creation as createClob() method threw error : java.lang.refl
ect.InvocationTargetException
[main] 2012-04-09 10:41:21,814 159382 DEBUG SettingsFactory - Automatic flush du
ring beforeCompletion(): disabled
[main] 2012-04-09 10:41:21,814 159382 DEBUG SettingsFactory - Automatic session 
close at end of transaction: disabled
[main] 2012-04-09 10:41:21,815 159383 DEBUG SettingsFactory - JDBC batch size: 3
0
[main] 2012-04-09 10:41:21,816 159384 DEBUG SettingsFactory - JDBC batch updates
 for versioned data: disabled
[main] 2012-04-09 10:41:21,816 159384 DEBUG SettingsFactory - Scrollable result 
sets: enabled
[main] 2012-04-09 10:41:21,817 159385 DEBUG SettingsFactory - Wrap result sets: 
disabled
[main] 2012-04-09 10:41:21,818 159386 DEBUG SettingsFactory - JDBC3 getGenerated
Keys(): enabled
[main] 2012-04-09 10:41:21,818 159386 DEBUG SettingsFactory - JDBC result set fe
tch size: 100
[main] 2012-04-09 10:41:21,819 159387 DEBUG SettingsFactory - Connection release
 mode: auto
[main] 2012-04-09 10:41:21,819 159387 INFO  TransactionFactoryInitiator - HHH000
399: Using default transaction strategy (direct JDBC transactions)
[main] 2012-04-09 10:41:21,844 159412 DEBUG SettingsFactory - Default batch fetc
h size: 1
[main] 2012-04-09 10:41:21,844 159412 DEBUG SettingsFactory - Generate SQL with 
comments: disabled
[main] 2012-04-09 10:41:21,845 159413 DEBUG SettingsFactory - Order SQL updates 
by primary key: disabled
[main] 2012-04-09 10:41:21,846 159414 DEBUG SettingsFactory - Order SQL inserts 
for batching: disabled
[main] 2012-04-09 10:41:21,846 159414 DEBUG SettingsFactory - Query translator: 
org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory
[main] 2012-04-09 10:41:21,867 159435 INFO  ASTQueryTranslatorFactory - HHH00039
7: Using ASTQueryTranslatorFactory
[main] 2012-04-09 10:41:21,867 159435 DEBUG SettingsFactory - Query language sub
stitutions: {}
[main] 2012-04-09 10:41:21,867 159435 DEBUG SettingsFactory - JPA-QL strict comp
liance: disabled
[main] 2012-04-09 10:41:21,868 159436 DEBUG SettingsFactory - Second-level cache
: enabled
[main] 2012-04-09 10:41:21,868 159436 DEBUG SettingsFactory - Query cache: disab
led
[main] 2012-04-09 10:41:21,869 159437 DEBUG SettingsFactory - Cache region facto
ry : org.hibernate.cache.internal.NoCachingRegionFactory
[main] 2012-04-09 10:41:21,872 159440 DEBUG SettingsFactory - org.hibernate.cach
e.internal.NoCachingRegionFactory did not provide constructor accepting java.uti
l.Properties; attempting no-arg constructor.
[main] 2012-04-09 10:41:21,873 159441 DEBUG SettingsFactory - Optimize cache for
 minimal puts: disabled
[main] 2012-04-09 10:41:21,873 159441 DEBUG SettingsFactory - Structured second-
level cache entries: disabled
[main] 2012-04-09 10:41:21,873 159441 DEBUG SettingsFactory - Statistics: disabl
ed
[main] 2012-04-09 10:41:21,874 159442 DEBUG SettingsFactory - Deleted entity syn
thetic identifier rollback: disabled
[main] 2012-04-09 10:41:21,874 159442 DEBUG SettingsFactory - Default entity-mod
e: pojo
[main] 2012-04-09 10:41:21,875 159443 DEBUG SettingsFactory - Named query checki
ng : enabled
[main] 2012-04-09 10:41:21,875 159443 DEBUG SettingsFactory - Check Nullability 
in Core (should be disabled when Bean Validation is on): enabled
[main] 2012-04-09 10:41:21,876 159444 DEBUG SettingsFactory - multi-tenancy stra
tegy : NONE

我已经做了这一点更多的研究，通过调试步进。我没有所有的源在我的类路径，但我仍然可以看到的变量。 Durring一个分钟的等待中，Hibernate查询pg_catalog.pg_type表：

[SELECT typname FROM pg_catalog.pg_type WHERE oid = , ]

下面是截图：

Answer 1:

我固定它=）我真的不得不四处根找到这个问题的答案。基本上，它归结为加载元数据和JDBC驱动程序。它装载的所有元数据，包括SQL列和其他各种结构，这是不需要操作旁边的意见。我不知道这是为什么在默认情况下，但你一定要关闭此功能，除非你明确地需要它：

config.setProperty("hibernate.temp.use_jdbc_metadata_defaults","false");

现在即时连接！

我能找到这个问题的唯一信息是代码：

107     // 'hibernate.temp.use_jdbc_metadata_defaults' is a temporary magic value.
108     // The need for it is intended to be alleviated with future development, thus it is
109     // not defined as an Environment constant...
110     //
111     // it is used to control whether we should consult the JDBC metadata to determine
112     // certain Settings default values; it is useful to *not* do this when the database
113     // may not be available (mainly in tools usage).
114     boolean useJdbcMetadata = ConfigurationHelper.getBoolean( "hibernate.temp.use_jdbc_metadata_defaults", configValues, true );

http://grepcode.com/file/repo1.maven.org/maven2/org.hibernate/hibernate-core/4.1.1.Final/org/hibernate/engine/jdbc/internal/JdbcServicesImpl.java#JdbcServicesImpl

Answer 2:

我只好也使hibernate.jdbc.use_get_generated_keys在以其他方式识别身份生成策略抛出异常。它启用之前自动根据从数据库收到的元数据。所以，我的整个的解决办法是添加以下两行persistence.xml中：

<property name="hibernate.jdbc.use_get_generated_keys" value="true" />
<property name="hibernate.temp.use_jdbc_metadata_defaults" value="false" />

Answer 3:

一个PostgreSQL服务器可以包含多个数据库。可惜的是，你不能隐藏其他的数据库metadatas一个连接，这就是为什么元数据读取由JDBC驱动程序需要很长的时间！

独立theese数据库到不同的Postgres的服务器和元数据读取的性能会有所提高！

了解如何在CentOS独立。

Answer 4:

我有滚动的结果集，这样的问题我不得不添加第三个参数，见下图：

<property name="hibernate.temp.use_jdbc_metadata_defaults">false</property>
<property name="hibernate.jdbc.use_get_generated_keys">true</property>
<property name="hibernate.jdbc.use_scrollable_resultset">true</property>

Answer 5:

将近7年后的今天，这仍是个问题......

开启“TEMP”键关机帮助，但它是一个滋扰，使性能一个接一个，这将是自动配置（见其他答案）。

在甲骨文和Teradata的情况下，我没有注意到这样的放缓，所以我挖深，发现其中最慢的部分是： https://github.com/pgjdbc/pgjdbc/blob/master/pgjdbc/src/main/java/组织/ PostgreSQL的/ JDBC / PgDatabaseMetaData.java＃L2237

此ResultSet在我的情况下，372行（类型）。然后，对每个驾驶员触发几个电话从https://github.com/pgjdbc/pgjdbc/blob/master/pgjdbc/src/main/java/org/postgresql/jdbc/TypeInfoCache.java#L204导致吨SQL语句对DB。

不知道如何，现在加快这，幸运的是，它需要一次，那么它的缓存。

Answer 6:

这听起来隐约就像我们在Ruby on Rails的看到了一个问题。你可能会寻找一个类似的原因是什么在这里描述我：

http://archives.postgresql.org/pgsql-performance/2009-11/msg00128.php

总之，这个问题是由多个类加载器上下文中的JDBC驱动程序的显式注册引起的。