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https://issues.apache.org/jira/browse/DIRSERVER-1377?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12721820#action_12721820
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Emmanuel Lecharny commented on DIRSERVER-1377:
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Well, you still have to handle all the cases, as a JdbmTable not allowing
duplicates will have a simple type *only* and the JdbmTable allowing duplicates
will allow *only* composite types. It just split the problem in two parts.
But IMO, you have to deal with simple type.
--- AvlTree manipulation ---
When you have deserialized the AvlTree, you have a data structure which is
totally thread safe. The problem is when you deserialize it from a byte[] which
is a reference to something that can be modified by another thread, as it's a
reference. If you do the de/ser into JDBM, as the retrieve/remove/put methos
are synchronized, this is safe, as no thread can touch the byte[] while you are
deserializing it.
Now, it will be costly. Another optuion would be to have a ByteArraySerializer
which just do a copy of the internal byte[], and returns this copy to the user.
The thread will then deserialize something that it owns. Same thing for
serialization, except that you don't need to copy the byte[], as it's produced
from scratch when serializing the tree.
IMO, this is probably the way to implement the fix : easy (no need to rewrite
all the existing marshallers) and will be faster than what we have in mind atm.
> Potential concurrency issue when adding/modifying/deleting entries at a high
> rate
> ---------------------------------------------------------------------------------
>
> Key: DIRSERVER-1377
> URL: https://issues.apache.org/jira/browse/DIRSERVER-1377
> Project: Directory ApacheDS
> Issue Type: Bug
> Affects Versions: 1.5.4
> Reporter: Emmanuel Lecharny
> Priority: Blocker
> Fix For: 1.5.5
>
>
> When adding/deleting entries with many clients (a client add and delete an
> entry many times), we may have some concurrency problem, as the index are
> updated without concurrent acces protection.
> Synchronizing the classes where we update the index might help.
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