5:09 p.m.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.4.sp1, 3.2.4, 3.2.3
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Priority: Minor
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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5:03 a.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Paul Smith commented on HHH-2645:
---------------------------------
We are seeing the same problem. Using Yourkit 6 monitor analyser we see this as the most
significant synchronization bottleneck. We're are currently forced to use Eager flush
mode (don't worry, we're planning to address that) so that flushmode is probably
exacerbating this with constant flushing.
I'm going to see if we can try the custom build using a java 5 concurrent reader hash
map, it's a good idea.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Priority: Minor
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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7:15 p.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Diego Pires Plentz commented on HHH-2645:
-----------------------------------------
Erik, can you attach a patch?
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Priority: Minor
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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11:12 a.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Erik Bergersjö commented on HHH-2645:
-------------------------------------
Afraid not, I'm not working for that customer at present, so I don't have the
code. However, only a single line of code needs to be changed and the description contains
both the old and the new version of that line.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Priority: Minor
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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2:12 a.m.
New subject: [Hibernate-JIRA] Updated: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Paul Cowan updated HHH-2645:
----------------------------
Attachment: concurrentreader.patch
Attached is a patch against 3.2.4sp1 which makes the change that Erik suggested.
Note that this isn't QUITE a 100% replacement; this will introduce 2 behavioural
changes which will need to be checked; I don't see either as being a problem from my
code inspection but I'm hardly an expert.
1) Previously, the code was using a SequencedHashMap; this guarantees insertion order when
navigating the entries in guessEntityMode(). This means that if the same Tuplizer is added
twice for two different EntityModes, then the behaviour of guessEntityMode changes from
'first-one-added wins' to 'who knows'. If the same Tuplizer cannot be
added twice (it seems so, from a code inspection of ComponentEntityModeToTuplizerMapping
and EntityEntityModeToTuplizerMapping, but I'm not 100% sure) then this is not an
issue.
2) ConcurrentReaderHashMap, like HashTable, does NOT allow null to be used as a key or
value. This is, again, a behaviour change, but again, from inspection of the above two
classes it's pretty clear that no nulls are ever passed in (in fact, they're
wrapped in an explicit check).
Otherwise, it's fairly straightforward.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Priority: Minor
Attachments: concurrentreader.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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4:11 p.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Tchavdar Roussanov commented on HHH-2645:
-----------------------------------------
We have the same issue running under Java 1.5. Our solution uses the new
java.util.concurrent.ConcurrentHashMap with one concurrent updater thread. We replaced the
same line with:
private final Map<EntityMode, Tuplizer> tuplizers = new
ConcurrentHashMap<EntityMode, Tuplizer>(64, 0.75f, 1);
Again it has a different behavior then the original but we did see any problem with our
code.
This is a very severe bottleneck and I think it should be tagged as major bug.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Priority: Minor
Attachments: concurrentreader.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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6:58 p.m.
New subject: [Hibernate-JIRA] Assigned: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Gail Badner reassigned HHH-2645:
--------------------------------
Assignee: Gail Badner
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
--
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7:42 p.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Diego Pires Plentz commented on HHH-2645:
-----------------------------------------
Just to remember, we can't use java 5+ features, since we must sill compatible with
java 1.4(at least)
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
--
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12:37 a.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Paul Cowan commented on HHH-2645:
---------------------------------
Just to clarify, the patch I attached doesn't use any Java 5 features, it's just
using Doug Lea's original concurrent library which is already used elsewhere in the
current codebase.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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4:01 a.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole commented on HHH-2645:
-------------------------------------
We do not use Doug Lea's concurrency package. It is included in the download, but
that is simply because it is a required dependency for JBossCache. If you do not use
JBossCache, right now you do not need that concurrency package either. So tis would
constitute a need for a new dependency...
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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3:49 a.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Paul Cowan commented on HHH-2645:
---------------------------------
Fair enough, Steve, I didn't realise that. I'm assuming from this that adding this
dependency is considered inappropriate. As this is a such a big performance hit for us
(And obviously others) what about the possibility of just including Doug Lea's
ConcurrentReaderHashMap in the code tree?
It's a single, standalone class (no dependencies on anything else in his package) and
as far as I can tell there are no license issues:
"All classes are released to the public domain and may be used for any purpose
whatsoever without permission or acknowledgment."
(from http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intr...)
Let me know if this is likely to be a suitable solution and I can prepare a new patch.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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6:02 p.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole commented on HHH-2645:
-------------------------------------
I am not saying that I would not consider using the oswego package (via dep or copying).
I am just pointing out that there would have to be a clear cut need to include the new
package.
As of this moment, I have not seen any hard facts showing that oswego's
ConcurrentReaderHashMap is any faster than say Hibernate's FastHashMap (originally
copied from commons-collection) or even the current code for that matter.
What I would ideally like to see is a series of tests showing the discrepancy. I tried
testing this in a non-concurrent env, but of course got no differences. I tried using
junitperf for the concurrent load testing, but that library is new to me and it was not
working out so well.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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6:31 p.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Tchavdar Roussanov commented on HHH-2645:
-----------------------------------------
The problem is not the speed of the hash map class but the usage of
Collections.synchronizedMap() wraper. To recreate the problem you need on object with
multiple collections and (in my case) code that forces session flush. Also you will have
to run with more than 20 threads running long enough to execute more then 1000
transactions.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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2:54 a.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole commented on HHH-2645:
-------------------------------------
1) I don't see where anyone is saying that using HashMap is the problem. In fact the
current Hibernate code is not even using HashMap, if you actually take a look. In fact
most comments are explicitly pointing to the use of synchronization as the cause. And
that probably is the case; call me pragmatic, I just prefer hard numbers.
2) This should be a *unit test* of the specific map usage pattern. We already have enough
integration tests that dont cover enough low-level details like this. We need to start
scaling out the test suite to contain both more unit tests and more load/perf tests.
3) Where did these numbers come from? I assume this is because you are discussing
integration tests and it took that long for you to get proper concurrent load on the Map
structure. This is another reason to have unit tests for this as well.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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12:19 p.m.
New subject: [Hibernate-JIRA] Updated: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Paul Cowan updated HHH-2645:
----------------------------
Attachment: maptest.patch
Attached is a very rough-and-ready, cobbled-together test which very approximately
demonstrates the problem and is fairly adjustable to show different alternatives for the
different 'real-world' scenarios people might be encountering. The patch should
apply cleanly to the 3.2.4sp1 codebase, which is what we're running; not sure how
cleanly it will apply elsewhere but it's extremely simple. It consists of 2 parts:
1) It changes EntityModeToTuplizerMapping to (optionally) take a Map implementation in the
constructor, defaulting to the current implementation (synchronized map wrapped around a
SequencedHashMap).
2) A simple test (not JUnit, just a main() method) which performs a very simple timing
test. It does 2 runs, one of which is thrown away and is just used to try and get the VM
up to speed with JITting etc. so as to produce a (slightly) more accurate result. The main
emphasis of the test is to create a number of threads, each of which will perform a
particular number of iterations. In each iteration, a certain number of guessEntityMode()s
and a certain number of getTuplizerOrNull()s will be performed against a very simple dummy
subclass of EntityModeToTuplizerMapping which in turn uses a simple dummied-out Tuplizer
implementation. The test is performed once using the current synchronised version, once
with FastHashMap, once with Doug Lea's ConcurrentHashMap, and once with his
ConcurrentReaderHashMap (obviously this requires the concurrent library to be on the
classpath).
It cuts a lot of corners, but it at least gives us something to work from. The behaviour
can be adjusted by modifying the values of the 6 constants at the top of the file. Running
20 threads, with a 20:1 getTuplizerOrNull():guessEntityMode() ratio (which is a very rough
attempt to recreate what we see in our system, in that we flush extremely frequently and I
gather this triggers the getTuplizerOrNull(); as far as I can tell guessEntityMode() is
most likely to be used in finding-by-example, which is rare in our application) on the
Server VM I get the following results:
Map class: class java.util.Collections$SynchronizedMap: 1510ms
Map class: class org.hibernate.util.FastHashMap: 292ms (x0.19337748344370861)
Map class: class EDU.oswego.cs.dl.util.concurrent.ConcurrentHashMap: 787ms
(x0.5211920529801325)
Map class: class EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap: 532ms
(x0.352317880794702)
which shows a ~3x speedup with ConcurrentReaderHashMap and a ~5x speedup with
FastHashMap.
If you play with the ratios, you'll see that the higher the ratio of tuplizer
gets:entity mode guesses, the bigger the problem is and the bigger improvements can be
gained. If you eliminate the guessEntityMode() calls completely (this is actually probably
closer to the real-world figure we get, though I don't have exact counts to hand) the
speedup is ~ 17x with FastHashMap.
From this, I would draw a few conclusions:
* Given that update
frequency is (as far as I can observe) close to zero -- I think these mappings are largely
set up once and forgotten? I may be wrong though -- FastHashMap is probably more than
sufficient, particularly given it's in the codebase already
* It may be worth considering changing FastHashMap into a more generic FastMap, which
takes in some sort of MapFactory. The default implementation could use HashMap, but the
TuplizerMapping could use SequencedHashMap to preserve existing behaviour (if this is
important).
I'd encourage people to calculate what loading makes this test (very roughly) reflect
any results they see in their application to check that our figures are not
'outliers' and we're operating off accurate data.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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2:19 p.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole commented on HHH-2645:
-------------------------------------
Thanks for that Paul. I'll start working with that.
The structure of this map was chosen largely because of future considerations. Mainly, I
want eventually to allow registration of custom entity-modes which would require
"later writes" into this map by the users. Additionally, I chose an ordered map
because I would want the Hibernate mappings considered first.
But as it is currently, neither of those is necessary. In fact, something I mentioned to
Gail that we should also take a look at was in fact not using a map at all here. It is
essentially a series of 3 options always right now...
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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6:24 a.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole commented on HHH-2645:
-------------------------------------
I took this maptest.patch stuff, modified it slighty and added timings for jdk5
ConcurrentHashMap also (just to see). I get slightly different results:
baseline : 9051 ms
FastHashMap : 8499 ms (ratio=0.9390123)
ConcurrentHashMap (jdk) : 509 ms (ratio=0.05623688)
ConcurrentHashMap (dl) : 6380 ms (ratio=0.7048945)
ConcurrentReaderHashMap (dl) : 3544 ms (ratio=0.39155895)
To be completely happy, I'd still want to average a couple of 'liveRun'
executions together rather than relying on one. I already added "forceful GC"
code to attempt to isolate the tests from GC from other tests. That would be all I could
think of to get the best results...
From my numbers, the JDK ConcurrentHashMap is clearly the best option,
but unfortunately not available as a solution until 4.0 when we move to jdk5. Other than
that, the Doug Lea / Oswego ConcurrentReaderHashMap seemed to significantly beat the
others for this access pattern.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
--
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7:24 a.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Paul Cowan commented on HHH-2645:
---------------------------------
Steve, are you able to post your modified test? It'd be useful for me to be able to
run it, that's a fairly hugely substantial different between the figures so I'm
curious as to what the difference is and if your changes give me substantially different
results also.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: concurrentreader.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
--
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1:37 p.m.
New subject: [Hibernate-JIRA] Updated: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole updated HHH-2645:
--------------------------------
Attachment: ConcurrentMapAcessPerformanceTest.java
Here you go.
I really liked the use of oswego to control the test threads, so i was looking at doing
something junitperf-like using that concept (curious where you found that). I'll look
at moving to use that today.
The biggest changes were:
1) the gc calls
2) doing the map filling one time rather than (included in timings) for each test
the rest were 'cosmetic'
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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12:05 p.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Paul Cowan commented on HHH-2645:
---------------------------------
Thanks Steve -- those results ARE extremely confusing, as I can reproduce your results on
my machine, but running MY version produces basically the same results as before. This, to
put not too fine a point on it, confused the @#$! out of me. After spending WAY too long
incrementally refactoring my code towards yours, though, continually running mine until I
got results like yours, I worked it out. There IS one subtle difference between our
codebases.
You have:
Map fastMap = new org.apache.commons.collections.FastHashMap();
where I had:
liveRun(new FastHashMap(), base);
with (drumroll):
import org.hibernate.util.FastHashMap;
org.hibernate.util.FastHashMap != org.apache.commons.collections.FastHashMap. D'oh!
Can't believe it took me that long to work it out. :)
If I amend your code to add:
Map fastMapHibernate = new org.hibernate.util.FastHashMap();
fastMapHibernate.put( EntityMode.DOM4J, tuplizer1 );
fastMapHibernate.put( EntityMode.POJO, tuplizer2 );
and the according dry + live runs, I get:
baseline : 2815 ms
FastHashMap (Apache) : 2576 ms (ratio=0.9150977)
FastHashMap (Hibernate) : 380 ms (ratio=0.13499112)
ConcurrentHashMap (jdk) : 473 ms (ratio=0.16802841)
ConcurrentHashMap (dl) : 1740 ms (ratio=0.6181172)
ConcurrentReaderHashMap (dl) : 1060 ms (ratio=0.37655416)
which neatly encapsulates the difference we got (again, this is with the server VM, the
proportions differ somewhat with the client VM but they're in the ballpark).
Why is this the case? Well, change the code to call .setFast(true) on the Apache map and
suddenly the figure drops to ~ the org.hibernate version. If the Apache one isn't in
fast mode, it's effectively fully synchronised (which explains why the performance is
close to the Collections.synchronizedMap wrapper).
So that explains that. Phew! Hopefully that gets us all on the same page.
2 other things:
1) Minor thing but, if you're thinking of landing this test in the codebase, check the
classname: 'Acess' -> 'Access'.
2) I don't know where the 'open the floodgates' latch-based concurrent test
idiom came from, to be honest. Been using it for a while; either stumbled upon it myself
one day or absorbed it by osmosis from a colleague, not sure. It's damn handy though!
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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1:38 p.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole commented on HHH-2645:
-------------------------------------
LOL, sorry, I actually intended that... not the confusion part ;) the "test
c-collections FastHashMap" part. But, yes I forgot about the 'fast switch'
on that impl
So then it looks like the Hibernate FastHashMap is actually the best option until we move
to JDK5, at which point I would drop it in favor of java.util.ConcurrentHashMap since (a)
the diff is statistically minor and (b) less for us to maintain.
so, I think we have a winner
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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12:03 a.m.
New subject: [Hibernate-JIRA] Updated: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Charles Crouch updated HHH-2645:
--------------------------------
Attachment: EntityModeToTuplizerMapping.patch
Any chance of this making it into 3.2.6? I've attached a patch which I think captures
the final decision on this bug.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
EntityModeToTuplizerMapping.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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7:07 a.m.
New subject: [Hibernate-JIRA] Closed: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Gail Badner closed HHH-2645.
----------------------------
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
EntityModeToTuplizerMapping.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
--
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7:07 a.m.
New subject: [Hibernate-JIRA] Resolved: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Gail Badner resolved HHH-2645.
------------------------------
Resolution: Fixed
Fix committed to trunk / 3.2.
I've added a constructor to EntityModeToTuplizerMapping with no arguments that creates
a org.hibernate.util.FastHashMap for the tuplizers. I've also added a constructor that
takes a Map argument to facilitate performance testing with various map implementation
(like the EntityModeToTuplizerMapping implementation in Paul Cowen's test).
All EntityModeToTuplizerMapping subclasses use the constructor with no arguments.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
EntityModeToTuplizerMapping.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
--
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6:59 a.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Paul Cowan commented on HHH-2645:
---------------------------------
This issue appears to be fixed in core/tags/v326, but doesn't show in the 3.2.6
release notes (I assume because this issue doesn't have a 'fix version').
Might want to amend that?
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
EntityModeToTuplizerMapping.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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3:01 p.m.
New subject: [Hibernate-JIRA] Reopened: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole reopened HHH-2645:
---------------------------------
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Fix For: 3.2.6
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
EntityModeToTuplizerMapping.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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3:01 p.m.
New subject: [Hibernate-JIRA] Resolved: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole resolved HHH-2645.
---------------------------------
Resolution: Fixed
Fix Version/s: 3.2.6
setting fixed version
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate3
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Fix For: 3.2.6
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
EntityModeToTuplizerMapping.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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9:39 p.m.
New subject: [Hibernate-JIRA] Commented: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole commented on HHH-2645:
-------------------------------------
Just wanted to point out that this has been fixed on trunk which will become 3.6 because
we moved to jdk 1.5 there as minimum.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate Core
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Fix For: 3.2.6
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
EntityModeToTuplizerMapping.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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9:41 p.m.
New subject: [Hibernate-JIRA] Issue Comment Edited: (HHH-2645) Synchronization bottleneck in EntityModeToTuplizerMapping
[
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645?page=c...
]
Steve Ebersole edited comment on HHH-2645 at 5/21/10 2:39 PM:
--------------------------------------------------------------
Just wanted to point out that this has been fixed on trunk which will become 3.6 because
we moved to jdk 1.5 there as minimum.
* by "this" I mean HHH-3050
was (Author: steve):
Just wanted to point out that this has been fixed on trunk which will become 3.6
because we moved to jdk 1.5 there as minimum.
Synchronization bottleneck in EntityModeToTuplizerMapping
---------------------------------------------------------
Key: HHH-2645
URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2645
Project: Hibernate Core
Issue Type: Patch
Components: core
Affects Versions: 3.2.3, 3.2.4, 3.2.4.sp1
Environment: Hibernate 3.2.3 (and later), Sun's JDK 1.4.2_12 (server VM) on
SunOS 5.10, Oracle 10g R2
Reporter: Erik Bergersjö
Assignee: Gail Badner
Priority: Minor
Fix For: 3.2.6
Attachments: ConcurrentMapAcessPerformanceTest.java, concurrentreader.patch,
EntityModeToTuplizerMapping.patch, maptest.patch
We have had a major performance bottleneck in EntityModeToTuplizerMapping with Hibernate
version 3.2.3 and the code for that class in 3.2.4sp1 is unchanged. We have found a
solution that solves the issue and would like to get it into the real version. I submitted
to the user forum first and was asked to create a JIRA issue.
The problematic line is:
private final Map tuplizers = Collections.synchronizedMap( new SequencedHashMap() );
We have changed it to (using util.concurrent):
private final Map tuplizers = new
EDU.oswego.cs.dl.util.concurrent.ConcurrentReaderHashMap();
This change alone makes our use cases six times faster. The difference is that
ConcurrentReaderHashMap handles concurrent readers much better, they don't have to
wait for each other.
The problem occurs when a high number of threads try to initialize sets (see mapping
below). A thread dump showed a high number of threads waiting for the same monitor, see
partial stack trace below.
The code runs on Sun's JDK 1.4.2_12 (server VM) on SunOS 5.10 and the kernel spends a
lot of time handling mutexes with the original implementation. That time disappears from
the radar screen with the fixed version.
Example mapping for set:
[code]
<set name="lines" lazy="true" inverse="true"
cascade="all-delete-orphan">
<key>
<column name="col1" not-null="true" />
<column name="col2" not-null="true" />
</key>
<one-to-many class="LineClass" />
</set>
[/code]
Stack trace (partial):
"Thread-108" prio=5 tid=0x05852e90 nid=0x103 waiting for monitor entry
[0x3ed7e000..0x3ed7fc28]
at java.util.Collections$SynchronizedMap.get(Collections.java:1942)
- waiting to lock <0x89d30788> (a java.util.Collections$SynchronizedMap)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizerOrNull(EntityModeToTuplizerMapping.java:53)
at
org.hibernate.tuple.EntityModeToTuplizerMapping.getTuplizer(EntityModeToTuplizerMapping.java:66)
at org.hibernate.type.ComponentType.getPropertyValues(ComponentType.java:353)
at org.hibernate.type.ComponentType.isEqual(ComponentType.java:141)
at org.hibernate.engine.CollectionKey.equals(CollectionKey.java:50)
at java.util.HashMap.eq(HashMap.java:274)
at java.util.HashMap.get(HashMap.java:323)
at
org.hibernate.engine.loading.CollectionLoadContext.getLocalLoadingCollectionEntry(CollectionLoadContext.java:163)
at
org.hibernate.engine.loading.CollectionLoadContext.locateLoadingCollectionEntry(CollectionLoadContext.java:150)
at
org.hibernate.engine.loading.CollectionLoadContext.getLoadingCollection(CollectionLoadContext.java:92)
at org.hibernate.loader.Loader.readCollectionElement(Loader.java:1003)
at org.hibernate.loader.Loader.readCollectionElements(Loader.java:646)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:591)
at org.hibernate.loader.Loader.doQuery(Loader.java:701)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.loadCollection(Loader.java:1994)
at
org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:36)
at
org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:565)
at
org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:60)
at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1716)
at
org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:344)
at
org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:86)
at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:163)
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5150
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6237
days old
hibernate-issues@lists.jboss.org
28 comments
8 participants
participants (8)
-
Charles Crouch (JIRA) -
Diego Pires Plentz (JIRA)
-
Erik Bergersjö (JIRA)
-
Gail Badner (JIRA)
-
Paul Cowan (JIRA)
-
Paul Smith (JIRA)
-
Steve Ebersole (JIRA)
-
Tchavdar Roussanov (JIRA)