Hi Angela,
thanks for taking the time to respond.
I did as you suggested and created a ticket here:
https://issues.apache.org/jira/browse/OAK-9158
Best regards,
Alex
Am 28.07.2020 um 10:10 schrieb Angela Schreiber:
Hi Alexander
Thanks for the detailed report and analysis.
May I suggest that you create a ticket at
https://issues.apache.org/jira/projects/OAK/issues
<https://issues.apache.org/jira/projects/OAK/issues> with component
documentmk providing all the details and attaching the patch? I think
that's the best way to move forward.
Unfortunately, I am not sufficiently familiar with that area of Oak to
review the proposed modification, but Marcel Reutegger and Julian
Reschke will for sure be able to provide you with feedback and
suggestions and I would suggest you ping them directly in the Jira ticket.
Kind regards
Angela
------------------------------------------------------------------------
*From:* Alexander Lüders <[email protected]>
*Sent:* Friday, July 24, 2020 3:19 PM
*To:* [email protected] <[email protected]>
*Subject:* Re: Slow performance in AbstractNodeState.equals
Hi again,
digging deeper I derived following patch which solved the performance
issue:
Index:
oak-store-document/src/main/java/org/apache/jackrabbit/oak/plugins/document/AbstractDocumentNodeState.java
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
---
oak-store-document/src/main/java/org/apache/jackrabbit/oak/plugins/document/AbstractDocumentNodeState.java
(revision 17ea60b0bfb0ca3670c99208170a774a6c99fdfc)
+++
oak-store-document/src/main/java/org/apache/jackrabbit/oak/plugins/document/AbstractDocumentNodeState.java
(date 1595575140063)
@@ -83,7 +83,11 @@
// revision does not match: might still be equals
} else if (that instanceof ModifiedNodeState) {
ModifiedNodeState modified = (ModifiedNodeState) that;
- if (modified.getBaseState() == this) {
+ NodeState baseState = modified.getBaseState();
+ if (baseState instanceof ModifiedDocumentNodeState) {
+ baseState = ((ModifiedDocumentNodeState)
baseState).getBaseState();
+ }
+ if (baseState == this) {
return EqualsDiff.equals(this, modified);
}
}
I am not entirely sure that this is correct but comparing with the
/ModifiedDocumentNodeState#equals/ method, I assume it to be.
The latter method compares the passed object with its baseState not
the /ModifiedDocumentNodeState/ instance itself. This is the prime
difference when comparing the differences of
/ModifiedDocumentNodeState#equals/ and /AbstractNodeDocumentState#equals/.
The patch above transfers that logic to
/AbstractNodeDocumentState#equals/.
What do you think?
Many thanks for your help.
Best regards,
Alexander Lüders
Am 23.07.2020 um 17:26 schrieb Alexander Lüders:
Dear Jackrabbit Oak developers,
we are currently trying to hunt down a performance issue we are
facing at a customer site.
We strongly need your help on this so any comments would be greatly
appreciated.
We have a MongoDB as a backend of a Oak repository where we see
hundreds of expensive queries being executed during a rather simple
operation.
It happens when we are saving a session in which we added a child
node to a node already containing a very large number of children.
This has not been the case with Jackrabbit Oak 1.4.8 and 1.4.26 but
it is an issue with 1.10.8 and 1.22.3.
Newer versions have not been tested yet but looking at the source we
believe that they will show that performance issue too.
What we know so far:
* The queries against the /MongoDocumentStore /are triggered via
/AbstractNodeState.equals/ (see stacktrace below)
* A TODO "inefficient unless there are very few child nodes" in that
method indicates poor performance but this has been there since a
long time and cannot explain the issue
* OAK-7401 introduced the class /ModifiedDocumentNodeState /class
which is not inheriting /ModifiedNodeState /or
/AbstractDocumentNodeState /(see class inheritance diagram)
*/AbstractDocumentNodeState#equals/ is checking against instances of
/ModifiedNodeState /and /AbstractDocumentNodeState /but not
/ModifiedDocumentNodeState/.
* /AbstractDocumentNodeState#equals/ triggers the "slow"
/AbstractNodeState#equals/ as a last resort
We definitely do not see the full picture yet but guessing from a
high-level perspective it looks like the introduction of
/ModifiedDocumentNodeState /broke the equals logic in class
/AbstractDocumentNodeState/.
Would you agree with that conclusion?
Is there anything further I can provide?
_/Stacktrace:/_
MongoDocumentStore.query(Collection<T>, String, String, String, long,
int) line: 609
MongoDocumentStore.query(Collection<T>, String, String, int) line: 598
DocumentNodeStore.readChildDocs(String, String, int) line: 1293
DocumentNodeStore.readChildren(AbstractDocumentNodeState, String,
int) line: 1233
DocumentNodeStore$7.call() line: 1185
DocumentNodeStore$7.call() line: 1182
LocalCache$LocalManualCache$1.load(Object) line: 4724
LocalCache$LoadingValueReference<K,V>.loadFuture(K, CacheLoader<?
super K,V>) line: 3522
LocalCache$Segment<K,V>.loadSync(K, int, LoadingValueReference<K,V>,
CacheLoader<? super K,V>) line: 2315
LocalCache$Segment<K,V>.lockedGetOrLoad(K, int, CacheLoader<? super
K,V>) line: 2278
LocalCache$Segment<K,V>.get(K, int, CacheLoader<? super K,V>) line: 2193
LocalCache<K,V>.get(K, CacheLoader<? super K,V>) line: 3932
LocalCache$LocalManualCache<K,V>.get(K, Callable<? extends V>) line: 4721
DocumentNodeStore.getChildren(AbstractDocumentNodeState, String, int)
line: 1182
DocumentNodeState.getChildNodeCount(long) line: 293
AbstractNodeState.equals(NodeState, NodeState) line: 375
DocumentNodeState(AbstractDocumentNodeState).equals(Object) line: 91
AbstractNodeState.equals(NodeState, NodeState) line: 384
DocumentNodeState(AbstractDocumentNodeState).equals(Object) line: 91
DocumentNodeStoreBranch$InMemory.setRoot(NodeState) line: 481
DocumentNodeStoreBranch.setRoot(NodeState) line: 111
DocumentRootBuilder.purge() line: 185
DocumentRootBuilder.merge(CommitHook, CommitInfo) line: 163
DocumentNodeStore.merge(NodeBuilder, CommitHook, CommitInfo) line: 1869
MutableRoot.commit(Map<String,Object>) line: 250
RepositoryImpl$1(SessionDelegate).commit(Root, String) line: 346
RepositoryImpl$1(SessionDelegate).save(String) line: 493
SessionImpl$8.performVoid() line: 424
RepositoryImpl$1(SessionDelegate).performVoid(SessionOperation<Void>)
line: 273
SessionImpl.save() line: 421
_/Class inheritance diagram:/_
Many thanks in advance for your help.
Best regards,
Alexander Lüders
--
Alexander Lüders, Entimo AG
Senior Software Engineer
Stralauer Platz 33-34 | 10243 Berlin | Germany
Tel +49(0)30 520 024 131
Fax +49(0)30 520 024 101
mailto:[email protected] |http://www.entimo.com
Vorstand: Marc Jantke (Vors.), Sven Prasse
Aufsichtratsvorsitzende: Erika Tannenbaum
Sitz der Gesellschaft: Berlin, Germany | Handelsregister: HRB
Berlin-Charlottenburg 85073
--
Alexander Lüders, Entimo AG
Senior Software Engineer
Stralauer Platz 33-34 | 10243 Berlin | Germany
Tel +49(0)30 520 024 131
Fax +49(0)30 520 024 101
mailto:[email protected] | http://www.entimo.com
Vorstand: Marc Jantke (Vors.), Sven Prasse
Aufsichtratsvorsitzende: Erika Tannenbaum
Sitz der Gesellschaft: Berlin, Germany | Handelsregister: HRB
Berlin-Charlottenburg 85073
