[OAK-701] Optimize Session.getNamespacePrefixes()

• Type: Sub-task
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.6
• Fix Version/s: 0.7
• Component/s: jcr
• Labels: performance
• Assignee: Marcel Reutegger
• Reporter: Marcel Reutegger
• Created: 19/Mar/13 09:00
• Updated: 31/Mar/15 08:26
• Resolved: 19/Mar/13 09:21

Description

Apache Sling uses Session.getNamespacePrefixes() quite often. E.g. when reading content through a JcrPropertyMap:

   java.lang.Thread.State: RUNNABLE
        at java.util.HashMap.put(HashMap.java:372)
        at org.apache.jackrabbit.oak.plugins.name.Namespaces.getNamespaceMap(Namespaces.java:64)
        at org.apache.jackrabbit.oak.plugins.name.ReadOnlyNamespaceRegistry.getPrefix(ReadOnlyNamespaceRegistry.java:116)
        at org.apache.jackrabbit.oak.jcr.SessionImpl.getNamespacePrefix(SessionImpl.java:529)
        - locked <0x00000007daf6c590> (a java.util.HashMap)
        at org.apache.jackrabbit.oak.jcr.SessionImpl.getNamespacePrefixes(SessionImpl.java:495)
        at org.apache.sling.jcr.resource.JcrPropertyMap.escapeKeyName(JcrPropertyMap.java:381)
        at org.apache.sling.jcr.resource.JcrPropertyMap.read(JcrPropertyMap.java:344)
        at org.apache.sling.jcr.resource.JcrPropertyMap.get(JcrPropertyMap.java:126)
        at org.apache.sling.jcr.resource.JcrPropertyMap.get(JcrPropertyMap.java:147)

I'd like to optimize the case when there are not session re-mapped namespaces. In this case the prefixes can be returned from the namespace registry as is. This avoids the loop and reduces calls on the Oak API. Initial testing shows a performance improvement by a factor of 3.

Issue Links

• relates to: OAK-2707 Performance: Consider cache for SessionImpl#getNamespacePrefixes