[jira] [Created] (HIVE-14778) document threading model of Streaming API

["Eugene Koifman (JIRA)" <ji...@apache.org>]

Eugene Koifman created HIVE-14778:
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             Summary: document threading model of Streaming API
                 Key: HIVE-14778
                 URL: https://issues.apache.org/jira/browse/HIVE-14778
             Project: Hive
          Issue Type: Bug
          Components: HCatalog, Transactions
    Affects Versions: 0.14.0
            Reporter: Eugene Koifman
            Assignee: Eugene Koifman


The model is not obvious and needs to be documented properly.

A StreamingConnection internally maintains 2 MetaStoreClient objects (each has 1 Thrift client for actual RPC). Let's call them "primary" and "heartbeat". Each TransactionBatch created from a given StreamingConnection, gets a reference to both of these MetaStoreClients. 
So the model is that there is at most 1 outstanding (not closed) TransactionBatch for any given StreamingConnection and for any given TransactionBatch there can be at most 2 threads accessing it concurrently. 1 thread calling TransactionBatch.heartbeat() (and nothing else) and the other calling all other methods.



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