Question

我很难调试这个问题。每当我尝试与postgres建立连接时，都需要一分钟。建立连接后，一切都很好。我已经尝试禁用所有映射而不加载任何映射，但仍然需要很长时间才能获取。我也试过禁用验证，没有区别。当我使用简单的简单JDBC连接时，它就是瞬间的。 Hibernate正在做一些花费大量时间的事情，我似乎无法缩小范围。非常感谢任何输入！

Postgres司机：

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>

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");

以下是发生延迟的代码段：

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;
    }

以下是日志结果：

[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

我已经对此进行了一些研究，逐步完成了调试器。我的类路径中没有所有源代码，但我仍然可以看到变量。留下一分钟等待，Hibernate正在查询pg_catalog.pg_type表：

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

以下是截图：

DebugWindow

Answer 1

我修好了它=）我真的不得不找到这个答案。基本上，它归结为加载元数据和JDBC驱动程序。它正在加载ALL META DATA，包括sql列和其他各种构造旁边的注释，这些注释不需要操作。我不知道为什么默认情况下会启用此功能，但除非您明确需要，否则您应该关闭此功能：

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

立即连接！

我能找到的唯一信息是代码：

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

我还必须启用hibernate.jdbc.use_get_generated_keys，否则身份生成策略会抛出异常。在根据从DB收到的元数据自动启用之前。所以我的整个解决方案是将以下两行添加到persistence.xml：

<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。不幸的是，你不能hide other-database metadatas to one connection，这就是为什么元数据读取需要jdbc-driver花费很长时间！

将theese数据库分成不同的postgres服务器，元数据阅读的性能将会提高！

阅读how to seperate on centos。

Answer 4

我在滚动结果集方面遇到问题，因此必须添加第3个参数，如下所示：

<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，这仍然是一个问题...

关闭“温度”键会有所帮助，但是启用将自动配置的属性的麻烦一事（请参阅其他答案）。

在使用Oracle和Teradata的情况下，我没有注意到这种放缓，因此我深入研究，发现最慢的部分在哪里： https://github.com/pgjdbc/pgjdbc/blob/master/pgjdbc/src/main/java/org/postgresql/jdbc/PgDatabaseMetaData.java#L2237

在我的情况下，此resultSet具有372行（类型）。然后，为每个驾驶员触发来自 https://github.com/pgjdbc/pgjdbc/blob/master/pgjdbc/src/main/java/org/postgresql/jdbc/TypeInfoCache.java#L204导致针对数据库的大量SQL语句。

不知道现在如何加快速度，幸运的是，它需要一次存储。

Answer 6

这听起来有点像我们在Ruby on Rails中看到的问题。你可能会找到我在这里描述的类似原因：

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

简而言之，该问题是由多个ClassLoader上下文中的JDBC驱动程序的显式注册引起的。

Hibernate慢慢收购Postgres连接

6 个答案: