Andrew Kyle Purtell created HBASE-23678:
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             Summary: Literate builder API for version management in schema
                 Key: HBASE-23678
                 URL: https://issues.apache.org/jira/browse/HBASE-23678
             Project: HBase
          Issue Type: Improvement
            Reporter: Andrew Kyle Purtell


Lars designed the combination of VERSIONS, TTL, MIN_VERSIONS, and 
KEEP_DELETED_CELLS with a maximum of flexibility. There is a lot of nuance 
regarding their usage. Almost all combinations of these four settings make 
sense for some use cases (exceptions are MIN_VERSIONS > 0 without TTL, and 
KEEP_DELETED_CELLS=TTL without TTL). There should be a way to make the behavior 
with TTL easier to conceive when creating the schema. This could take the form 
of a literate builder API for ColumnDescriptor or an extension to an existing 
one. 

Let me give you a motivating example: We may want to retain all versions for a 
given TTL, and then only a specific number of versions. This can be achieved 
with VERSIONS=INT_MAX, TTL=_retention_interval_, KEEP_DELETED_CELLS=TTL, 
MIN_VERSION=_num_versions_ . This is not intuitive though because VERSIONS has 
been used to specify _num_versions_ in this example since version 0.1.

A literate builder API, by way if its method names, could let a user describe 
more or less in speaking language how they want version retention to work, and 
internally the builder API could set the low level schema attributes. 



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