Jesus Camacho Rodriguez created HIVE-19027:
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Summary: Make materializations invalidation cache work with
multiple active remote metastores
Key: HIVE-19027
URL: https://issues.apache.org/jira/browse/HIVE-19027
Project: Hive
Issue Type: Improvement
Components: Materialized views
Affects Versions: 3.0.0
Reporter: Jesus Camacho Rodriguez
Assignee: Jesus Camacho Rodriguez
The main points:
- Only MVs stored in transactional tables can have a time window value of 0.
Those are the only MVs that can be guaranteed to not be outdated when a query
is executed, if we use custom storage handlers to store the materialized view,
we cannot make any promises.
- For MVs that +cannot be outdated+, we do not check the metastore. Instead,
comparison is based on valid write id lists.
- For MVs that +can be outdated+, we still rely on the invalidation cache.
** The window for valid outdated MVs can be specified in intervals of 1 minute
(less than that, it is difficult to have any guarantees about whether the MV is
actually outdated by less than a minute or not).
** The async loading is done every interval / 2 (or probably better, we can
make it configurable).
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