[jira] [Commented] (HIVE-12421) Streaming API TransactionBatch.beginNextTransaction() does not wait for locks

["Alan Gates (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-12421?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15009159#comment-15009159 ] 

Alan Gates commented on HIVE-12421:
-----------------------------------

[~roshan_naik] can comment further, but I think the thinking was some writers have no ability to buffer their inbound data, so blocking on a lock could force them to drop data.  We should change this to have the writer pass a maximum wait time.  If this code fails to obtain a lock in the allowed time then it can throw an exception that makes clear what happened and let the writer decide what to do from there.

> Streaming API TransactionBatch.beginNextTransaction() does not wait for locks
> -----------------------------------------------------------------------------
>
>                 Key: HIVE-12421
>                 URL: https://issues.apache.org/jira/browse/HIVE-12421
>             Project: Hive
>          Issue Type: Bug
>          Components: HCatalog, Transactions
>    Affects Versions: 0.14.0
>            Reporter: Eugene Koifman
>            Assignee: Eugene Koifman
>
> TransactionBatchImpl.beginNextTransactionImpl() has
> {noformat}
>         LockResponse res = msClient.lock(lockRequest);
>         if (res.getState() != LockState.ACQUIRED) {
>           throw new TransactionError("Unable to acquire lock on " + endPt);
>         }
> {noformat}
> This means that if there are any competing locks already take, this will throw an Exception to client.  This doesn't seem like the right behavior.  It should block.
> We could also add TransactionBatch.beginNextTransaction(long timeoutMs) to  give the client more control.
> cc [~alangates]  [~sriharsha]



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