[ACCUMULO-2362] Reduce blocking in client API (Tables)

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 1.4.4, 1.5.0
• Component/s: client
• Assignee: Unassigned
• Reporter: Josh Elser
• Created: 12/Feb/14 21:26
• Updated: 04/Apr/15 02:54
• Resolved: 04/Apr/15 02:54

Description

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.