Sushanth Sowmyan created HIVE-14841:
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Summary: Replication - Phase 2
Key: HIVE-14841
URL: https://issues.apache.org/jira/browse/HIVE-14841
Project: Hive
Issue Type: New Feature
Components: repl
Affects Versions: 2.1.0
Reporter: Sushanth Sowmyan
Per email sent out to the dev list, the current implementation of replication
in hive has certain drawbacks, for instance :
* Replication follows a rubberbanding pattern, wherein different
tables/ptns can be in a different/mixed state on the destination, so
that unless all events are caught up on, we do not have an equivalent
warehouse. Thus, this only satisfies DR cases, not load balancing
usecases, and the secondary warehouse is really only seen as a backup,
rather than as a live warehouse that trails the primary.
* The base implementation is a naive implementation, and has several
performance problems, including a large amount of duplication of data
for subsequent events, as mentioned in HIVE-13348, having to copy out
entire partitions/tables when just a delta of files might be
sufficient/etc. Also, using EXPORT/IMPORT allows us a simple
implementation, but at the cost of tons of temporary space, much of
which is not actually applied at the destination.
Thus, to track this, we now create a new branch (repl2) and a uber-jira(this
one) to track experimental development towards improvement of this situation.
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