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in J2EE environment Entity Manager will automatically close at the end of your EJB method.<br />
If you open it manually / not use it in EJB methods, you have to close it manually as well.
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in J2EE environment Entity Manager will automatically close at the end of your EJB method.
If you open it manually / not use it in EJB methods, you have to close it manually as well.

<div>
can I ask if I call em.close(), does that guarantee to close the db connection?
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can I ask if I call em.close(), does that guarantee to close the db connection?

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<div class="content wysiwyg-content">
I am using a reusable EntityManager design, similar to <br />
<a href="http://blog.julianpaas.com/?p=65" rel="ugc">http://blog.julianpaas.com/?p=65</a><br />
<br />
according to this approach, the EntityManager is kept alive (does not call em.close), so it is reused within a thread. <br />
<br />
after running my program for a while, I start to get<br />
<br />
org.postgresql.util.PSQLEx<wbr />ception: FATAL: sorry, too many clients already<br />
<br />
I am wondering if this is due to the fact I don't call em.close, and some how, too many threads ended up using too many connections. <br />
<br />
It is a big change if I add in em.close every where. I wonder if someone can give me a tip whether this is the area of suspect, or there is some other way I can resolve this out of connection error.<br />
<br />
I am using c3p0 connection pooling with max_size set at 20.
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</div>


I am using a reusable EntityManager design, similar to 
http://blog.julianpaas.com/?p=65

according to this approach, the EntityManager is kept alive (does not call em.close), so it is reused within a thread. 

after running my program for a while, I start to get

org.postgresql.util.PSQLException: FATAL: sorry, too many clients already

I am wondering if this is due to the fact I don't call em.close, and some how, too many threads ended up using too many connections. 

It is a big change if I add in em.close every where. I wonder if someone can give me a tip whether this is the area of suspect, or there is some other way I can resolve this out of connection error.

I am using c3p0 connection pooling with max_size set at 20.

FATAL: sorry, too many clients already

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