aem apache-oak

OAK Query Aborted

Evgeniy Fitsner Software Engineer
1 min read
OAK Query Aborted

Every Adobe Experience Manager developer encounters an exception indicating that the node reading limit has been exceeded:

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java.lang.UnsupportedOperationException: The query read or traversed more than 100000 nodes. 
To avoid affecting other tasks, processing was stopped.
	at org.apache.jackrabbit.oak.query.FilterIterators.checkReadLimit(FilterIterators.java:70)
	at org.apache.jackrabbit.oak.plugins.index.Cursors.checkReadLimit(Cursors.java:67)
	at org.apache.jackrabbit.oak.plugins.index.lucene.LucenePropertyIndex$LucenePathCursor$1.next(LucenePropertyIndex.java:1730)
	at org.apache.jackrabbit.oak.plugins.index.lucene.LucenePropertyIndex$LucenePathCursor$1.next(LucenePropertyIndex.java:1711)
	at com.google.common.collect.Iterators$7.computeNext(Iterators.java:646)
	at com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:143)
	at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138)
	at org.apache.jackrabbit.oak.plugins.index.Cursors$PathCursor.hasNext(Cursors.java:216)
	at org.apache.jackrabbit.oak.plugins.index.lucene.LucenePropertyIndex$LucenePathCursor.hasNext(LucenePropertyIndex.java:1751)
	at org.apache.jackrabbit.oak.query.ast.SelectorImpl.next(SelectorImpl.java:432)
	at org.apache.jackrabbit.oak.query.QueryImpl$RowIterator.fetchNext(QueryImpl.java:824)
	at org.apache.jackrabbit.oak.query.QueryImpl$RowIterator.hasNext(QueryImpl.java:851)
	at org.apache.jackrabbit.oak.jcr.query.QueryResultImpl$1.fetch(QueryResultImpl.java:98)

Solutions

In this situation, developers can:

  • Define an Oak index for the query
  • Redesign repository taxonomy or structure for improvement
  • Update Oak indexes to cover the query
  • Use oak:Unstructured instead of nt:unstructured and sling:Folder instead of sling:OrderedFolder when ordering is not required
  • Consider other architectural approaches

Development Workaround

During development, you can temporarily increase LimitReads and LimitInMemory parameters:

  1. Navigate to QueryEngineSettings at http://localhost:4502/system/console/jmx/org.apache.jackrabbit.oak%3Aname%3Dsettings%2Ctype%3DQueryEngineSettings
  2. Increase the selected parameters

Note: This is for development only; do not deploy to production.