<style>
/* Changing the layout to use less space for mobiles */
@media screen and (max-device-width: 480px), screen and (-webkit-min-device-pixel-ratio: 2) {
#email-body { min-width: 30em !important; }
#email-page { padding: 8px !important; }
#email-banner { padding: 8px 8px 0 8px !important; }
#email-avatar { margin: 1px 8px 8px 0 !important; padding: 0 !important; }
#email-fields { padding: 0 8px 8px 8px !important; }
#email-gutter { width: 0 !important; }
}
</style>
<div id="email-body">
<table id="email-wrap" align="center" border="0" cellpadding="0" cellspacing="0" style="background-color:#f0f0f0;color:#000000;width:100%;">
<tr valign="top">
<td id="email-page" style="padding:16px !important;">
<table align="center" border="0" cellpadding="0" cellspacing="0" style="background-color:#ffffff;border:1px solid #bbbbbb;color:#000000;width:100%;">
<tr valign="top">
<td bgcolor="#3e4c4e" style="background-color:#3e4c4e;color:#ffffff;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;line-height:1;"><img src="https://www.jboss.org/dms/hibernate/images/jira/jiraheader_hibernate.png" alt="" style="vertical-align:top;" /></td>
</tr><tr valign="top">
<td id="email-banner" style="padding:32px 32px 0 32px;">
<table align="left" border="0" cellpadding="0" cellspacing="0" width="100%" style="width:100%;">
<tr valign="top">
<td style="color:#505050;font-family:Arial,FreeSans,Helvetica,sans-serif;padding:0;">
<img id="email-avatar" src="https://hibernate.onjira.com/secure/useravatar?avatarId=10162" alt="" height="48" width="48" border="0" align="left" style="padding:0;margin: 0 16px 16px 0;" />
<div id="email-action" style="padding: 0 0 8px 0;font-size:12px;line-height:18px;">
<a class="user-hover" rel="juliusdev" id="email_juliusdev" href="https://hibernate.onjira.com/secure/ViewProfile.jspa?name=juliusdev" style="color:#6c797f;">Julien Brulin</a>
created <img src="https://hibernate.onjira.com/images/icons/bug.gif" height="16" width="16" border="0" align="absmiddle" alt="Bug"> <a style='color:#6c797f;text-decoration:none;' href='https://hibernate.onjira.com/browse/HHH-7926'>HHH-7926</a>
</div>
<div id="email-summary" style="font-size:16px;line-height:20px;padding:2px 0 16px 0;">
<a style='color:#6c797f;text-decoration:none;' href='https://hibernate.onjira.com/browse/HHH-7926'><strong>HQL SqlFragment Memory Leak</strong></a>
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</table>
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<td id="email-fields" style="padding:0 32px 32px 32px;">
<table border="0" cellpadding="0" cellspacing="0" style="padding:0;text-align:left;width:100%;" width="100%">
<tr valign="top">
<td id="email-gutter" style="width:64px;white-space:nowrap;"></td>
<td>
<table border="0" cellpadding="0" cellspacing="0" width="100%">
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<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 10px 10px 0;white-space:nowrap;">
<strong style="font-weight:normal;color:#505050;">Issue Type:</strong>
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<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
<img src="https://hibernate.onjira.com/images/icons/bug.gif" height="16" width="16" border="0" align="absmiddle" alt="Bug"> Bug
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<strong style="font-weight:normal;color:#505050;">Affects Versions:</strong>
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<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
4.1.9 </td>
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<strong style="font-weight:normal;color:#505050;">Assignee:</strong>
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<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
Unassigned </td>
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<strong style="font-weight:normal;color:#505050;">Components:</strong>
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<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
query-hql </td>
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<strong style="font-weight:normal;color:#505050;">Created:</strong>
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<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
16/Jan/13 9:21 AM
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<strong style="font-weight:normal;color:#505050;">Description:</strong>
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<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
<p style='margin-top:0;margin-bottom:10px;'> have a simple webapp deployed on a Tomcat server. The webapp is a REST web-service, each web resource load data from a MySQL database and returns an XML or JSON document. I use the following frameworks stack : Jersey (1.14) + Spring (3.1) + Hibernate (4.1) + EHCache (2.5.1).</p>
<p style='margin-top:0;margin-bottom:10px;'>I tested the webapp with jMeter : I started 5 threads to request the web resources. After few minutes, the heap has started to fill slowly to reach 99% and finally return an OOM exception . I don't know if it's a memory leak but when I see a tons of org.hibernate.hql.internal.ast.tree.SqlFragment objects in the memory heap ?!!</p>
<p style='margin-top:0;margin-bottom:10px;'>/usr/java/jdk/bin/jmap -histo:live 17047 > /tmp/histo.txt</p>
<p style='margin-top:0;margin-bottom:10px;'> num #instances #bytes class name<br/>
----------------------------------------------<br/>
1: 720143 69133728 org.hibernate.hql.internal.ast.tree.SqlFragment<br/>
2: 510537 63559320 [C<br/>
3: 360221 34581216 org.hibernate.hql.internal.ast.tree.BinaryLogicOperatorNode<br/>
4: 704652 33823296 java.util.HashMap$Entry<br/>
5: 360223 31699624 org.hibernate.hql.internal.ast.tree.SqlNode<br/>
6: 697354 27894160 java.lang.String<br/>
7: 370975 26710200 org.hibernate.hql.internal.ast.tree.Node<br/>
8: 171241 25623320 <constMethodKlass><br/>
9: 208125 24948176 [Ljava.lang.Object;<br/>
10: 171241 20568632 <methodKlass><br/>
11: 16012 17827384 <constantPoolKlass><br/>
12: 383070 16623136 [I<br/>
13: 34829 15170176 [Ljava.util.HashMap$Entry;<br/>
14: 226869 12885896 <symbolKlass><br/>
15: 16012 12590168 <instanceKlassKlass><br/>
Here my jvm options :</p>
<p style='margin-top:0;margin-bottom:10px;'>JAVA_OPTS="-Xms1g -Xmx1g -XX:MaxPermSize=512m -XX:+UseConcMarkSweepGC -XX:+CMSClas</p>
<p style='margin-top:0;margin-bottom:10px;'>I tested all my REST resources with jmeter to identify which resource leak. I found 1 resource, now I can fill all the memory heap in less than 30s with jmeter. I found the HQL query which create lots of SqlFragment :</p>
<p style='margin-top:0;margin-bottom:10px;'>String q = "select p from PhysicalItem p where p.product.id=:itemid and p.fileType in (:filetypes) order by p.id desc";<br/>
return sessionFactory.getCurrentSession().createQuery(q).setParameter("itemid", logicalItemID).setParameterList("filetypes", fileTypes).list();<br/>
Here the number of SqlFragment just after starting Tomcat.</p>
<p style='margin-top:0;margin-bottom:10px;'>jmap -histo:live 27472 | grep -i SqlFragment<br/>
608: 15 840 org.hibernate.hql.internal.ast.tree.SqlFragment<br/>
And the number of SqlFragment after 1 http request + a full garbage</p>
<p style='margin-top:0;margin-bottom:10px;'>jmap -histo:live 27472 | grep -i SqlFragment<br/>
503: 37 2072 org.hibernate.hql.internal.ast.tree.SqlFragment<br/>
To fix quickly this issue I rewrote the HQL request to SQL :</p>
<p style='margin-top:0;margin-bottom:10px;'>String sql = "select p.* from physical_item p where p.id_logical = :itemid and p.file_type in (:filetypes) order by p.id desc";<br/>
List<String> names = new ArrayList<String>();<br/>
for (FileType fileType : fileTypes) {
names.add(fileType.getName());
}<br/>
return sessionFactory.getCurrentSession()<br/>
.createSQLQuery(sql)<br/>
.addEntity(PhysicalItem.class)<br/>
.setParameter("itemid", logicalItemID)<br/>
.setParameterList("filetypes", names)<br/>
.list();</p>
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<strong style="font-weight:normal;color:#505050;">Environment:</strong>
</td>
<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
Spring 3.1.x, Jersey 1.14, Tomcat 7.0.27
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<strong style="font-weight:normal;color:#505050;">Project:</strong>
</td>
<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
<a style="color:#6c797f;" href="https://hibernate.onjira.com/browse/HHH">Hibernate ORM</a>
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<strong style="font-weight:normal;color:#505050;">Priority:</strong>
</td>
<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
<img src="https://hibernate.onjira.com/images/icons/priority_major.gif" height="16" width="16" border="0" align="absmiddle" alt="Major"> Major
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<strong style="font-weight:normal;color:#505050;">Reporter:</strong>
</td>
<td style="color:#000000;font-family:Arial,FreeSans,Helvetica,sans-serif;font-size:12px;padding:0 0 10px 0;width:100%;">
<a class="user-hover" rel="juliusdev" id="email_juliusdev" href="https://hibernate.onjira.com/secure/ViewProfile.jspa?name=juliusdev" style="color:#6c797f;">Julien Brulin</a>
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