Sergey Shelukhin reassigned HIVE-17657:

    Assignee: Sergey Shelukhin

> export/import for MM tables is broken
> -------------------------------------
>                 Key: HIVE-17657
>                 URL: https://issues.apache.org/jira/browse/HIVE-17657
>             Project: Hive
>          Issue Type: Sub-task
>          Components: Transactions
>            Reporter: Eugene Koifman
>            Assignee: Sergey Shelukhin
>            Priority: Major
>              Labels: mm-gap-2
> there is mm_exim.q but it's not clear from the tests what file structure it 
> creates 
> On import the txnids in the directory names would have to be remapped if 
> importing to a different cluster.  Perhaps export can be smart and export 
> highest base_x and accretive deltas (minus aborted ones).  Then import can 
> ...?  It would have to remap txn ids from the archive to new txn ids.  This 
> would then mean that import is made up of several transactions rather than 1 
> atomic op.  (all locks must belong to a transaction)
> One possibility is to open a new txn for each dir in the archive (where 
> start/end txn of file name is the same) and commit all of them at once (need 
> new TMgr API for that).  This assumes using a shared lock (if any!) and thus 
> allows other inserts (not related to import) to occur.
> What if you have delta_6_9, such as a result of concatenate?  If we stipulate 
> that this must mean that there is no delta_6_6 or any other "obsolete" delta 
> in the archive we can map it to a new single txn delta_x_x.
> Add read_only mode for tables (useful in general, may be needed for upgrade 
> etc) and use that to make the above atomic.

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