[
https://issues.apache.org/jira/browse/ACCUMULO-2362?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13905725#comment-13905725
]
Josh Elser commented on ACCUMULO-2362:
--------------------------------------
Agreed. I know that at least one place would be creating (Batch)Scanners which
should be rather easy to replicate.
When I was looking at the MultiTableBatchWriter for ACCUMULO-1833, I evaluated
"less" blocking mostly by looking at JVisualVM or timed how long N threads
which contend against each other take to complete. Any better ideas than that?
> Reduce blocking in client API (Tables)
> --------------------------------------
>
> Key: ACCUMULO-2362
> URL: https://issues.apache.org/jira/browse/ACCUMULO-2362
> Project: Accumulo
> Issue Type: New Feature
> Components: client
> Affects Versions: 1.4.4, 1.5.0
> Reporter: Josh Elser
> Fix For: 1.7.0
>
>
> Presently, the {{Tables}} class contains a static map of instance to ZooCache
> that *many* of the classes in the client API use. The problem with this is
> that many of the methods on ZooCache ultimately are synchronized. When
> multiple threads using Connectors, TableOperations, Scanners/BatchScanners,
> and BatchWriters against the same Accumulo instance, you currently have a
> massive synchronization problem.
> We should give some thought to heavy, concurrent access to Accumulo client
> API calls within the same JVM. Consideration should also be given to the
> consistency of wrapping zookeeper with a cache like is presently done.
--
This message was sent by Atlassian JIRA
(v6.1.5#6160)
