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https://issues.apache.org/jira/browse/JCR-2950?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13615456#comment-13615456
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Cameron Hinkle commented on JCR-2950:
-------------------------------------
Can anyone summarize the state of this ticket? We ran into this condition when
our CQ5 servers received a huge wall of traffic all at once and even when the
traffic levels went back down to normal, the servers never recovered. There
were couple hundred AJP threads on each server all waiting for the same locked
object.
I'm not clear on whether a patch has been committed that eases this contention
in a later release (we're on CQ5.5, Jackrabbit 2.4) or are there steps we can
take our current version to help in this scenario? Thanks.
> CachingEntryCollector ineffective if number of accessed policies exceeds
> cache size
> -----------------------------------------------------------------------------------
>
> Key: JCR-2950
> URL: https://issues.apache.org/jira/browse/JCR-2950
> Project: Jackrabbit Content Repository
> Issue Type: Improvement
> Components: jackrabbit-core, security
> Affects Versions: 2.2.12, 2.4.2, 2.6
> Environment: Repository with ACEs > 1000
> Reporter: Honwai Wong
> Assignee: Julian Reschke
> Attachments: auth-prefilled-cache.csv, cache-empty-aces.csv,
> cache-empty-aces.png, cache-empty-aces-scfixed.csv,
> CachingEntryCollector.ConcurrentCache-trunk.patch, jcr-2950-2.csv,
> jcr-2950-2.png, JCR-2950-concurrent-cache-2.patch, jcr-2950.csv,
> jcr-2950-csv.sh, JCR-2950_entryseparation-multisessionhack.patch,
> JCR-2950_entryseparation.patch, JCR-2950-futures_2.patch,
> JCR-2950-futures_3.patch, JCR-2950-futures_4.patch, JCR-2950-futures.patch,
> JCR-2950_performance_tests.patch.gz, jcr-2950.png, JCR-2950-refactor.patch,
> JCR-2950-refactor+rootnode_2.patch , JCR-2950-refactor+rootnode_3.patch,
> JCR-2950-refactor+rootnode_4.patch, JCR-2950-refactor+rootnode_5.patch,
> JCR-2950-refactor+rootnode_6.patch, JCR-2950-refactor+rootnode_7.patch,
> JCR-2950-refactor+rootnode.patch, JCR-2950-throttle2.patch,
> JCR-2950-throttle.patch, syssessioncomparison.csv, test2950.sh
>
>
> The CachingEntryCollector's cache (LRUMap, max size: 1000) seems to become
> ineffective in case there are more than 1000 ACEs present in the repository.
> Since access to the cache is synchronized, many threads are basically
> blocked, waiting to get access to the cache.
> Java callstack:
> at
> org/apache/jackrabbit/core/security/authorization/acl/CachingEntryCollector.getEntries(CachingEntryCollector.java:99(Compiled
> Code))
> at
> org/apache/jackrabbit/core/security/authorization/acl/EntryCollector.collectEntries(EntryCollector.java:134(Compiled
> Code))
> at
> org/apache/jackrabbit/core/security/authorization/acl/CompiledPermissionsImpl.canRead(CompiledPermissionsImpl.java:250(Compiled
> Code))
> at
> org/apache/jackrabbit/core/security/DefaultAccessManager.canRead(DefaultAccessManager.java:251(Compiled
> Code))
> at
> org/apache/jackrabbit/core/ItemManager.canRead(ItemManager.java:426(Compiled
> Code))
> at
> org/apache/jackrabbit/core/ItemManager.createItemData(ItemManager.java(Compiled
> Code))
> at
> org/apache/jackrabbit/core/ItemManager.getItemData(ItemManager.java:379(Compiled
> Code))
> at
> org/apache/jackrabbit/core/ItemManager.itemExists(ItemManager.java:292(Compiled
> Code))
> at
> org/apache/jackrabbit/core/ItemManager.itemExists(ItemManager.java:464(Compiled
> Code))
> at
> org/apache/jackrabbit/core/session/SessionItemOperation$1.perform(SessionItemOperation.java:49(Compiled
> Code))
> at
> org/apache/jackrabbit/core/session/SessionItemOperation$1.perform(SessionItemOperation.java:46(Compiled
> Code))
> at
> org/apache/jackrabbit/core/session/SessionItemOperation.perform(SessionItemOperation.java:187(Compiled
> Code))
> at
> org/apache/jackrabbit/core/session/SessionState.perform(SessionState.java:200(Compiled
> Code))
> at
> org/apache/jackrabbit/core/SessionImpl.perform(SessionImpl.java:355(Compiled
> Code))
> at
> org/apache/jackrabbit/core/SessionImpl.itemExists(SessionImpl.java:751(Compiled
> Code))
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