Geoffrey Jacoby created HBASE-23602:
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             Summary: TTL Before Which No Data is Purged
                 Key: HBASE-23602
                 URL: https://issues.apache.org/jira/browse/HBASE-23602
             Project: HBase
          Issue Type: New Feature
            Reporter: Geoffrey Jacoby


HBase currently offers operators a choice. They can set KEEP_DELETED_CELLS=true 
and VERSIONS to max value, plus no TTL, and they will always have a complete 
history of all changes (but high storage costs and penalties to read 
performance). Or they can have KEEP_DELETED_CELLS=false and VERSIONS/TTL set to 
some reasonable values, but that means that major compactions can destroy the 
ability to do a consistent snapshot read of any prior time. (This limits the 
usefulness and correctness of, for example, Phoenix's SCN lookback feature.) 

I propose having a new TTL property to give a minimum age that an expired or 
deleted Cell would have to achieve before it could be purged. (I see that 
HBASE-10118 already does something similar for the delete markers themselves.) 

This would allow operators to have a consistent history for some finite amount 
of recent time while still purging out the "long tail" of obsolete / deleted 
versions. 



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