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Bug
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Resolution: Fixed
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High
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5.10.2, 5.10.8, 6.6.3
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23
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Severity 2 - Major
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121
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Summary
Corrupted entries in the application Ancestors Table (responsible for maintaining the relationship in between parent and descendant pages on Confluence) can cause View Page threads to run for a long period, triggering symptoms like High CPU Usage and intense GC Activity.
Symptoms & Diagnosis
This problem is triggered regardless of environmental variables, but its symptoms are usually the following:
- High CPU Usage.
- Garbage Collection Threads being heavily used.
Also, it is important to diagnose if there are corrupted entries in the Ancestors Table or not, since those are known to cause this issue.
In order to diagnose if there are indeed corrupted entries in the Ancestors Table, an administrator may run the query below at Confluence's database:
SELECT A.ANCESTORID, A.DESCENDENTID, COUNT(A.DESCENDENTID) FROM CONFANCESTORS A, CONTENT B WHERE B.CONTENTID = A.DESCENDENTID GROUP BY A.ANCESTORID, A.DESCENDENTID HAVING COUNT(A.DESCENDENTID) != 1 ORDER BY 3 DESC
If any results are returned, the CONFANCESTORS table is corrupt and needs to be rebuilt.
Cause
This is caused by corrupted entries in the application Ancestors Table - Responsible for maintaining the relationship in between parent and descendant pages on Confluence.
Thread dump example
Thread Dumps will usually show that the offending threads are executing the getInheritedContentPermissionSets (accountable for checking permissions) method being executed:
"http-nio-8090-exec-20 uri:/pages/viewpage.action username:john.smith" #274 daemon prio=5 os_prio=0 tid=0x00007f6484011000 nid=0x2e8b runnable [0x00007f61c350f000] java.lang.Thread.State: RUNNABLE at net.sf.hibernate.impl.AbstractVisitor.processValue(AbstractVisitor.java:67) at net.sf.hibernate.impl.AbstractVisitor.processValues(AbstractVisitor.java:36) at net.sf.hibernate.impl.SessionImpl.isUpdateNecessary(SessionImpl.java:2666) at net.sf.hibernate.impl.SessionImpl.flushEntity(SessionImpl.java:2581) at net.sf.hibernate.impl.SessionImpl.flushEntities(SessionImpl.java:2513) at net.sf.hibernate.impl.SessionImpl.flushEverything(SessionImpl.java:2308) at net.sf.hibernate.impl.SessionImpl.autoFlushIfRequired(SessionImpl.java:1831) at net.sf.hibernate.impl.SessionImpl.getQueries(SessionImpl.java:1594) at net.sf.hibernate.impl.SessionImpl.find(SessionImpl.java:1559) at net.sf.hibernate.impl.QueryImpl.list(QueryImpl.java:49) at com.atlassian.confluence.security.persistence.dao.hibernate.HibernateContentPermissionSetDao.lambda$getInheritedContentPermissionSets$0(HibernateContentPermissionSetDao.java:38) at com.atlassian.confluence.security.persistence.dao.hibernate.HibernateContentPermissionSetDao$$Lambda$766/775792763.doInHibernate(Unknown Source) at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:370) at org.springframework.orm.hibernate.HibernateTemplate.executeFind(HibernateTemplate.java:341) at com.atlassian.confluence.security.persistence.dao.hibernate.HibernateContentPermissionSetDao.getInheritedContentPermissionSets(HibernateContentPermissionSetDao.java:25) ...
Workaround
The workaround consists of re-constructing the application Ancestors Table as described in Rebuilding the Ancestor Table documentation:
- Back up your database.
- Use the following URL to access the Page Level Permissions page: <base-url>/admin/permissions/pagepermsadmin.action
- Choose Rebuild ancestor table.
- Go to
> General Configuration > Cache Management. - Flush the Inherited Content Permissions cache (only).
You may also need to rebuild the content index so that the permissions take effect in search results.