marco polo created ACCUMULO-3982:
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Summary: Add LRU mechanism to address memory concerns and possibly
pre-fetch entries
Key: ACCUMULO-3982
URL: https://issues.apache.org/jira/browse/ACCUMULO-3982
Project: Accumulo
Issue Type: New Feature
Components: client, tserver
Affects Versions: 1.7.0, 1.6.3, 1.8.0
Reporter: marco polo
Fix For: 1.8.0
On larger systems, especially those of which may split frequently, I've seen
churn in the TabletLocator caches. Could we possibly pre-fetch entries for a
table so that we don't constantly access the metadata table for tablet
locations.
Additionally, instead of clearing the cache in the case of a miss or failure,
could we simply update those entries in the cache? If we do this we may
minimize cache misses overall and the need to scan the meta data table. If need
be, we could have a threshold before clearing the cache entirely if people see
the need for that.
It would also be helpful to add an LRU cache ( or maybe even priority based LRU
cache ). In ACCUMULO-3549, we added a cache clear to TabletServer to avoid
overwhelming memory. An LRU cache might address this concern and make the clear
cache call unnecessary.
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