Glassfish 2.1 从不重用 Postgresql 和 Eclipselink 的语句？
我们使用 Glassfish 服务器 2.1 和 Eclipselink JPA 2.1 并连接到 PostgreSQL 数据库 8.4.8。 问题是，在 Postgres 的日志文件中，我总是看到使用 em.createQuery 或 em.createNamedQuery 创建的语句的准备。 似乎已经准备好的语句都没有被重用。所以表现真的很差。
我尝试将默认 JDBC 设置prepareThreshold 从 5 设置为 1。 这只改变了未命名的语句现在被命名了。但它们仍然没有被重用。
我还尝试了连接池的几种设置，因为准备好的语句依赖于连接，但返回到默认的 org.postgresql.ds.PGSimpleDataSource 和 javax.sql.DataSouce。
我还在 persistence.xml 中启用了语句缓存：
Glassfish 2.1 是否支持语句缓存？如果确实如此，我错过了哪些设置？
任何提示表示赞赏。
We are using Glassfish server 2.1 with Eclipselink JPA 2.1 and connect to a PostgreSQL database 8.4.8.
The problem is that in the log file of Postgres I always see a prepare of the statements that were created with em.createQuery or em.createNamedQuery.
It seems that no statement that has been prepared is reused. Therefore the performance is really bad.
I tried setting the default JDBC setting prepareThreshold from 5 to 1.
That only changed that the unnamed statements were now named. But they were still not reused.
I also tried several settings for the connection pooling as prepared statements are connection dependent but returned to the default org.postgresql.ds.PGSimpleDataSource and javax.sql.DataSouce.
I enabled statement caching also in the persistence.xml:
<property name="eclipselink.jdbc.cache-statements" value="true"/>
Does Glassfish 2.1 support statement caching? And if it does what are the settings I missed?
Any hints appreciated.
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考虑到这一点：http://www.youtube.com/watch?v=hfx_M0p0KoM好像2.1不支持语句缓存。
Considering this: http://www.youtube.com/watch?v=hfx_M0p0KoM it seems that 2.1 does not support statement caching.
为了完整起见：
以下是 GlassFish 3.1 中语句缓存设置的链接：
http://download.oracle.com/docs /cd/E18930_01/html/821-2418/giyck.html#giyci
以下是详细解释新功能的开发者博客文章：
http://blogs.oracle.com/technical/entry/statement_caching_in_glassfish_v3
For completeness:
Here is the link to the statement caching setting in GlassFish 3.1:
http://download.oracle.com/docs/cd/E18930_01/html/821-2418/giyck.html#giyci
Here is a developer blog entry explaining the new feature in detail:
http://blogs.oracle.com/technical/entry/statement_caching_in_glassfish_v3